Magnetoresistive effect element, magneto-resistive effect head, method for manufacturing the same and magnetic recording apparatus using the same

ABSTRACT

A magnetoresistive effect element which is easy to manufacture and in which a sense current is prevented from bypassing a barrier layer is provided. Also provided are a method for manufacturing the element and a magnetic recording apparatus utilizing the element. This magnetoresistive effect element utilizes an MTJ film which comprises, for forming its basic structure, a free layer, a barrier layer, a pinned layer and a pinning layer, wherein an oxide or a nitride layer is formed by oxidizing or nitriding metallic materials constituting the pinned layer and pinning layer.

TECHNICAL FIELD

[0001] This invention relates to a magnetic device including amagnetoresistive element such as a magnetic head for recording aninformation signal on and/or reading/reproducing an information signalfrom a magnetic medium, a method for manufacturing such a head and amagnetic recording apparatus using such a head.

[0002] This application is based on Japanese Patent Application No. Hei11-1153051, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0003] Various documents disclose a transducer for the magnetic datareading called a magnetoresistive sensor (hereinafter referred to as “MRsensor”) or head, and it has been known that such a sensor can read datafrom a magnetized surface at a high linear density. The MR sensordetects a magnetic field signal through a change in resistance which issensed by a read element as a function of the strength and direction ofthe magnetic flux. This type of conventional MR sensor operates based onthe anisotropic magnetoresistive effect (hereinafter referred to as “AMReffect”) in which one component of the resistance of the read elementchanges in proportion to the square of the cosine of the angle betweenthe direction of magnetization and the direction of the sense currentflowing through the element. The AMR effect is described in detail by D.A. Thompson et al. in the article “Memory, Storage and RelatedApplications”, IEEE Trans. on Mag. MAG-11, page 1039 (1975). In magneticheads utilizing the AMR effect, a longitudinal bias is often applied tosuppress Barkhausen noise wherein an antiferromagnetic material such asFeMn, NiMn and nickel oxide is used as the longitudinal biasingmaterial.

[0004] Recently, some documents have described a more remarkablemagnetoresistive effect in which the change in resistance in a laminatedmagnetic sensor is caused by a spin-dependent transmission of conductionelectrons between magnetic layers through a nonmagnetic layer and theaccompanying spin-dependent scattering at the interface of the layers.This magnetoresistive effect is called by various names such as “giantmagnetoresistive effect” and “spin-valve effect”. This type ofmagnetoresistive sensor is made of appropriate materials and has animproved sensitivity and a larger resistance change as compared to thoseobserved in a sensor utilizing the AMR effect. In an MR sensor of thistype, the resistance in a plane between a pair of ferromagnetic layersseparated by a nonmagnetic layer changes in proportion to the cosine ofthe angles between the directions of magnetization of the two layers.

[0005] Japanese Unexamined Patent Application, First Publication No.Hei. 2-61572 which claims a priority of June 1988 discloses a laminatedmagnetic structure which can provide a large MR change caused by anantiparallel alignment of magnetizations in the magnetic layers. Thespecification of this publication refers to ferromagnetic transitionmetals and alloys as materials which can be used in the laminatedstructure. It also discloses a structure in which a pinning layer isadded to at least one of the two ferromagnetic layers separated by anintermediate layer, and the fact that FeMn is suitable for the pinninglayer.

[0006] Japanese Unexamined Patent Application, First Publication No.Hei. 4-103014 filed on Aug. 22, 1990, describes a ferromagnetic tunneljunction film which takes the form of a multilayer film having anintermediate layer inserted between ferromagnetic layers, wherein abiasing magnetic field from an antiferromagnetic material is applied toat least one of the ferromagnetic layers.

[0007] Japanese Unexamined Patent Application, First Publication No. Hei10-162327 which claims a priority of Nov. 27, 1996 describes about anexample of reproducing heads with a ferromagnetic tunnel junction filmwhich has such a structure that a layer (longitudinal biasing layer) forcontrolling magnetic domains in the free layer does not contact the freelayer, wherein a film of a material other than the metallic materialsconstituting the ferromagnetic tunnel junction film is formed.

[0008] There has been proposed a shield type magnetoresistive effectelement utilizing a ferromagnetic tunnel junction film which has such astructure that the longitudinal biasing layer is prevented from directlycontacting the ferromagnetic tunnel junction film by means of aninsulating material such as alumina (see Japanese Unexamined PatentApplication, First Publication No. Hei 10-162327). This is to solve theproblem that, although in the case of a shield type element with aferromagnetic tunnel junction a sense current should flow through thetunnel junction portion perpendicularly thereto, with a structuresimilar to that of the conventional shield type element utilizing a spinvalve a sense current bypasses the barrier layer and flows through thelongitudinal biasing portion which is located near the barrier layer andhas lower resistance value than that of the barrier layer, as a resultof which the sense current does not contribute to the detection of theresistance change. However, since this structure is attained by means ofa process of further forming a film of alumina upon end portions of theferromagnetic tunnel junction film formed by patterning in advance,during the patterning process of the ferromagnetic tunnel junction film,metal is scattered when patterning those of the layers constituting theferromagnetic tunnel junction film which are disposed below the barrierlayer, and the scattered metal is redeposited on side walls of thoselayers including the barrier layers which have already been patterned.Consequently, the sense current bypasses the barrier layer and flowsthrough the redeposited layer in the finished element, causing the MRratio to be significantly reduced.

SUMMARY OF THE INVENTION

[0009] It is therefore an object of the present invention to provide amagnetoresistive effect element which is easy to manufacture and inwhich the sense current is prevented from bypassing the barrier layer.

[0010] It is another object of the invention to provide a method formanufacturing such a magnetoresistive effect element.

[0011] It is a further object of the invention to provide an apparatuswhich uses such a magnetoresistive effect element.

[0012] In the first aspect of the present invention, a magnetoresistiveeffect element comprising: a ferromagnetic tunnel junction film whichcomprises, for forming a basic structure thereof, an arrangement of afree layer, a barrier layer formed on the free layer and a pinned layerformed on the barrier layer or an arrangement of a pinned layer, abarrier layer formed on the last-mentioned pinned layer and a free layerformed on the last-mentioned barrier layer, wherein pattern of theferromagnetic tunnel junction film comprises an oxide or a nitride of ametallic material constituting the ferromagnetic tunnel junction film.

[0013] In the second aspect of the invention, a magnetoresistive effectelement comprising: a ferromagnetic tunnel junction film whichcomprises, for forming a basic structure thereof, an arrangement of afree layer, a barrier layer formed on the free layer, a pinned layerformed on the barrier layer and a pinning layer formed on the pinnedlayer or an arrangement of a pinning layer, a pinned layer formed on thelast-mentioned pinning layer, a barrier layer formed on thelast-mentioned pinned layer and a free layer formed on thelast-mentioned barrier layer, wherein a pattern of the ferromagnetictunnel junction film comprises an oxide or a nitride of a metallicmaterial constituting the ferromagnetic tunnel junction film.

[0014] In the third aspect of the invention, a magnetoresistive effectelement comprising: a ferromagnetic tunnel junction film whichcomprises, for forming a basic structure thereof, an arrangement of anunderlayer, a free layer formed on the underlayer, a barrier layerformed on the free layer, a pinned layer formed on the barrier layer anda pinning layer formed on the pinned layer or an arrangement of anunderlayer, a pinning layer formed on the last-mentioned underlayer, apinned layer formed on the last-mentioned pinning layer, a barrier layerformed on the last-mentioned pinned layer and a free layer formed on thelast-mentioned barrier layer, wherein a pattern of the ferromagnetictunnel junction film comprises an oxide or a nitride of a metallicmaterial constituting the underlayer.

[0015] In the fourth aspect of the invention, a magnetoresistive effectelement comprising: a ferromagnetic tunnel junction film whichcomprises, for forming a basic structure thereof, an arrangement of afree layer, a barrier layer formed on the free layer, a pinned layerformed on the barrier layer, a pinning layer formed on the pinned layerand a protective layer formed on the pinning layer or an arrangement ofa pinning layer, a pinned layer formed on the last-mentioned pinninglayer, a barrier layer formed on the last-mentioned pinned layer, a freelayer formed on the last-mentioned barrier layer and a protective layerformed on the last-mentioned free layer, wherein a pattern of theferromagnetic tunnel junction film comprises an oxide or a nitride of ametallic material constituting the protective layer.

[0016] In the fifth aspect of the invention, a magnetoresistive effectelement comprising: a substrate; a lower shield layer formed on thesubstrate; a lower electrode layer, at least a portion of which isformed on the lower shield layer or combined with the lower shieldlayer; a longitudinal biasing layer formed on the lower electrode layerand patterned so as to have a width which is smaller than that of thelower shield layer when viewed from an air-bearing surface of the head;a ferromagnetic tunnel junction film which comprises, for forming abasic structure thereof, an arrangement of a free layer, a barrier layerformed on the free layer, a pinned layer formed on the barrier layer anda pinning layer formed on the pinned layer or an arrangement of apinning layer, a pinned layer formed on the last-mentioned pinninglayer, a barrier layer formed on the last-mentioned pinned layer and afree layer formed on the last-mentioned barrier layer, at least a partof the free layer being disposed above the longitudinal biasing layerand adjoining the longitudinal biasing layer directly or with anunderlayer interposed therebetween; an insulating layer formed at leaston a part of the free layer and the longitudinal biasing layer; an upperelectrode layer formed above the pinning layer and adjoining, at leastat a part thereof, the pinning layer directly or with a protective layerinterposed therebetween; and an upper shield layer, at least a part ofwhich is formed on or combined with the upper electrode layer; whereinan oxide or a nitride of a metallic material constituting theferromagnetic tunnel junction film is present at an end portion or aperipheral portion of a pattern of the ferromagnetic tunnel junctionfilm.

[0017] In the sixth aspect of the invention, a magnetoresistive effectelement comprising: a substrate; a lower shield layer formed on thesubstrate; a lower electrode layer, at least a portion of which isformed on or combined with the lower shield layer; a longitudinalbiasing layer formed on the lower electrode layer and patterned so as tohave a width which is smaller than that of the lower shield layer whenviewed from an air-bearing surface of the head; a ferromagnetic tunneljunction film which comprises, for forming a basic structure thereof, anarrangement of a free layer, a barrier layer formed on the free layer, apinned layer formed on the barrier layer and a pinning layer formed onthe pinned layer or an arrangement of a pinning layer, a pinned layerformed on the last-mentioned pinning layer, a barrier layer formed onthe last-mentioned pinned layer and a free layer formed on thelast-mentioned barrier layer, at least a part of the free layer beingdisposed below the longitudinal biasing layer and adjoining thelongitudinal biasing layer directly or with an underlayer interposedtherebetween; an insulating layer formed on at least a part of the freelayer and the longitudinal biasing layer; an upper electrode layerformed on the pinning layer and adjoining, at least at a portionthereof, the pinning layer directly or with a protective layerinterposed therebetween; and an upper shield layer, at least a part ofwhich is formed on or combined with the upper electrode layer; whereinan oxide or a nitride of a metallic material constituting theferromagnetic tunnel junction film is present at an end portion or aperipheral portion of a pattern of the ferromagnetic tunnel junctionfilm.

[0018] In the seventh aspect of the invention, a magnetoresistive effectelement comprising: a substrate; a lower shield layer formed on thesubstrate; a lower electrode layer, at least a portion of which isformed on or combined with the lower shield layer; a ferromagnetictunnel junction film which comprises, for forming a basic structurethereof, an arrangement of a free layer, a barrier layer formed on thefree layer, a pinned layer formed on the barrier layer and a pinninglayer formed on the pinned layer or an arrangement of a pinning layer, apinned layer formed on the last-mentioned pinning layer, a barrier layerformed on the last-mentioned pinned layer and a free layer formed on thelast-mentioned barrier layer, the film being formed on the lowerelectrode layer, the free layer having a width equal to or less thanthat of the lower electrode layer when viewed from an air-bearingsurface of the element; a longitudinal biasing film comprising a filmformed by laminating an insulating layer, at least a portion of whichadjoins the free layer, and a longitudinal biasing layer formed on theinsulating layer, or an insulating material; an upper electrode layerdisposed above the free layer and adjoining, at least at a portionthereof, the free layer directly or with a protective layer interposedtherebetween; and an upper shield layer, at least a part of which isformed on or combined with the upper electrode layer; wherein an oxideor a nitride of a metallic material constituting the ferromagnetictunnel junction film is present at an end portion or a peripheralportion of a pattern of the ferromagnetic tunnel junction film.

[0019] In the eighth aspect of the invention, a magnetoresistive effectelement comprising: a substrate; a lower shield layer formed on thesubstrate; a lower electrode layer, at least a portion of which isformed on or combined with the lower shield layer; a ferromagnetictunnel junction film which comprises, for forming a basic structurethereof, an arrangement of a free layer, a barrier layer formed on thefree layer, a pinned layer formed on the barrier layer and a pinninglayer formed on the pinned layer or an arrangement of a pinning layer, apinned layer formed on the last-mentioned pinning layer, a barrier layerformed on the last-mentioned pinned layer and a free layer formed on thelast-mentioned barrier layer, the film being formed on the lowerelectrode layer, the free layer having a width equal to or less thanthat of the lower electrode layer when viewed from an air-bearingsurface of the element; an insulating layer adjoining at a part thereofthe free layer; a longitudinal biasing layer disposed above the freelayer and adjoining, at least at a part thereof, the free layer directlyor with an interface control layer interposed therebetween; an upperelectrode layer disposed above the longitudinal biasing layer andadjoining, at least at a portion thereof, the longitudinal biasinglayer; and an upper shield layer, at least a part of which is formed onor combined with the upper electrode layer; wherein an oxide or anitride of a metallic material constituting the ferromagnetic tunneljunction film is present at an end portion or a peripheral portion of apattern of the ferromagnetic tunnel junction film.

[0020] In the ninth aspect of the invention, a method for manufacturinga magnetoresistive effect element which utilizes as its magnetoresistiveeffect element a ferromagnetic tunnel junction film comprising the stepsof: forming a basic structure of the ferromagnetic tunnel junction film,an arrangement of a free layer, a barrier layer formed on the free layerand a pinned layer formed on the barrier layer or an arrangement of apinned layer, a barrier layer formed on the last-mentioned pinned layerand a free layer formed on the last-mentioned barrier layer; and afterpatterning the ferromagnetic tunnel junction film, oxidizing ornitriding an end portion of the patterned ferromagnetic tunnel junctionfilm.

[0021] In the tenth aspect of the invention, a method for manufacturinga magnetoresistive effect element which utilizes as its magnetoresistiveeffect element a ferromagnetic tunnel junction film comprising the stepsof: forming a basic structure of the ferromagnetic tunnel junction film,an arrangement of a free layer, a barrier layer formed on the freelayer, a pinned layer formed on the barrier layer and a pinning layerformed on the pinned layer or an arrangement of a pinning layer, apinned layer formed on the last-mentioned pinning layer, a barrier layerformed on the last-mentioned pinned layer and a free layer formed on thelast-mentioned barrier layer; when the ferromagnetic tunnel junctionfilm is patterned, stopping patterning the film in the middle of thelayers constituting the magnetoresistive effect element; and oxidizingor nitriding at least a surface of that region of the magnetoresistiveelement at which the patterning has been stopped in the middle.

[0022] In the eleventh aspect of the invention, a magnetoresistiveconversion system comprising: a magnetoresistive sensor comprising amagnetoresistive effect element; a current generating circuit forgenerating a current to be passed through the magnetoresistive sensor;and a data reading circuit for detecting a change in resistivity of themagnetoresistive sensor as a function of a detected magnetic field.

[0023] In the twelfth aspect of the invention, a magnetic storage systemcomprising: a magnetic recording medium having a plurality of tracks fordata recording; a magnetoresistive conversion system; a first actuatorfor moving the magnetoresistive conversion system to a selected track onthe magnetic recording medium; and a second actuator for driving themagnetic recording medium so as to rotate the magnetic recording medium.

[0024] In the case of the above-described magnetoresistive effectelements, after the ferromagnetic tunnel junction film (hereinafterreferred to as “MTJ film”) is formed, a layer composed of an oxide ornitride of the metallic materials constituting the pinned and pinninglayers can be formed by oxidizing or nitriding the sidewall portions ofat least the pinned and pinning layers of the MTJ film. Thus, themagnetoresistive effect head according to the invention is quite easy tomanufacture. Even when a redeposited layer of metal is formed on thesidewalls of the MTJ film thus patterned, it is possible to prevent acurrent from bypassing the barrier layer by oxidizing or nitriding theredeposited layer in the manufacturing process, since an oxide or anitride formed thereby is an insulator and does not contribute toelectric conduction. The yield can thus be improved.

[0025] Furthermore, it will be possible to obtain a magnetoresistiveeffect element which has little noise in its reproduction signalwaveform, a higher S/N (Signal to Noise) ratio and a lower error rate.It is also possible to construct a high-performance magnetic recording(or recording/reproducing) apparatus by the employment of thismagnetoresistive effect element.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026]FIG. 1 is a schematic side sectional view of a magnetoresistiveeffect element provided in accordance with a first embodiment of theinvention;

[0027]FIG. 2 is a schematic side sectional view of anothermagnetoresistive effect element provided in accordance with the firstembodiment of the invention;

[0028]FIG. 3 is a schematic side sectional view of a furthermagnetoresistive effect element provided in accordance with the firstembodiment of the invention;

[0029]FIG. 4 is a schematic side sectional view of a furthermagnetoresistive effect element provided in accordance with the firstembodiment of the invention;

[0030]FIG. 5 is a schematic side sectional view of a furthermagnetoresistive effect element provided in accordance with the firstembodiment of the invention;

[0031]FIG. 6 is a schematic side sectional view of a furthermagnetoresistive effect element provided in accordance with the firstembodiment of the invention;

[0032]FIG. 7 is a schematic side sectional view of a furthermagnetoresistive effect element provided in accordance with the firstembodiment of the invention;

[0033]FIG. 8 is a schematic side sectional view of a furthermagnetoresistive effect element provided in accordance with the firstembodiment of the invention;

[0034]FIG. 9 is a schematic side sectional view of a furthermagnetoresistive effect element provided in accordance with the firstembodiment of the invention;

[0035]FIG. 10 is a schematic side sectional view of a furthermagnetoresistive effect element provided in accordance with the firstembodiment of the invention;

[0036]FIG. 11 is a schematic side sectional view of a furthermagnetoresistive effect element provided in accordance with the firstembodiment of the invention;

[0037]FIG. 12 is a schematic side sectional view of a furthermagnetoresistive effect element provided in accordance with the firstembodiment of the invention;

[0038]FIG. 13 is a schematic side sectional view of a magnetoresistiveeffect element provided in accordance with a second embodiment of theinvention;

[0039]FIG. 14 is a schematic side sectional view of a magnetoresistiveeffect element provided in accordance with a third embodiment of theinvention;

[0040]FIG. 15 is a schematic side sectional view of anothermagnetoresistive effect element provided in accordance with the thirdembodiment of the invention;

[0041]FIG. 16 is a schematic side sectional view of a magnetoresistiveeffect element provided in accordance with a fourth embodiment of theinvention;

[0042]FIG. 17 is a schematic side sectional view of a magnetoresistiveeffect element provided in accordance with a fifth embodiment of theinvention;

[0043]FIG. 18 is a schematic side sectional view of a magnetoresistiveeffect element provided in accordance with a sixth embodiment of theinvention;

[0044]FIG. 19 is a schematic plan view of the magnetoresistive effectelement provided in accordance with the first embodiment of theinvention of FIG. 1;

[0045]FIG. 20 is a schematic plan view of the magnetoresistive effectelement provided in accordance with the second embodiment of theinvention of FIG. 13;

[0046]FIG. 21 is a schematic plan view of the magnetoresistive effectelement provided in accordance with the third embodiment of theinvention of FIG. 14;

[0047]FIG. 22 is a schematic plan view of the magnetoresistive effectelement provided in accordance with the fourth embodiment of theinvention of FIG. 16;

[0048]FIG. 23 is a schematic plan view of the magnetoresistive effectelement provided in accordance with the fifth embodiment of theinvention of FIG. 17;

[0049]FIGS. 24A to 24I are illustrations showing in plan view themagnetoresistive effect element according to the first embodiment invarious manufacturing steps;

[0050]FIGS. 25A to 25H are illustrations showing in plan view themagnetoresistive effect element according to the second embodiment invarious manufacturing steps;

[0051]FIGS. 26A to 26H are illustrations showing in plan view themagnetoresistive effect element according to the third embodiment invarious manufacturing steps;

[0052]FIGS. 27A to 27F are illustrations showing in plan view themagnetoresistive effect element according to the fifth embodiment invarious manufacturing steps;

[0053]FIG. 28 is a perspective view of a part of a recording/reproducingelement to which a magnetoresistive effect element according to thepresent invention is applied; and

[0054]FIG. 29 is a diagram showing a magnetoresistive conversion systemwhich comprises the magnetic recording/reproducing head shown in FIG.28.

[0055]FIG. 30 is a diagram showing an example of a magnetic recordingsystem which utilizes the magnetoresistive conversion system shown inFIG. 29.

[0056]FIG. 31 is an illustration schematically showing a magneticrecording/reproducing apparatus in which a magnetoresistive effectelement according to the invention is used.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

[0057] Magnetoresistive effect elements provided in accordance with thefirst to sixth embodiments of the invention will now be described withreference to the accompanying drawings.

[0058] [First Embodiment]

[0059]FIG. 1 is an illustration showing a magnetoresistive effectelement according to the first embodiment in cross-section parallel toits air-bearing surface (hereinafter referred to “ABS”).

[0060] In this arrangement, a lower shield layer 11 and a lowerelectrode layer 12 are deposited on a substrate (not shown). Upon theselayers, a free layer 2 and a barrier layer 3 are sequentially deposited.A pinned layer 4, a pinning layer 5 and an upper electrode layer 14 aredeposited on the barrier layer 3 between right and left longitudinalbiasing layers 6 and then patterned as shown in FIG. 1. A layer made ofan oxide or nitride of the metallic materials constituting the pinnedand pinning layers 4 and 5 (i.e., oxide or nitride of the metallicmaterials constituting a ferromagnetic tunnel junction film) is formedon the side walls of the patterned pinned and pinning layers 4 and 5.Such layer will hereinafter be called as “oxide layer” and “nitridelayer” and designated by reference numeral 1. Insulating layers 13 areprovided on the right and left sides of the layers 1. On these layers,an upper electrode layer 14 and an upper shield layer 15 are furtherdeposited.

[0061] The portion constituted by the lamination of free layer 2/barrierlayer 3/pinned layer 4/pinning layer 5 corresponds to an MTJ film(ferromagnetic tunnel junction film).

[0062]FIG. 19 is a plan view of the above magnetoresistive effectelement. In FIG. 19, shown at A is a portion where a lamination of lowershield layer 11/lower electrode layer 12/free layer 2/barrier layer3/insulating layer 13 is provided. Similarly, B represents the portionwhere a lamination of lower shield layer 11/lower electrode layer12/free layer 2/barrier layer 3/insulating layer 13 is provided, C theportion where a lamination of lower shield layer 11/lower electrodelayer 12/longitudinal biasing layer 6/free layer 2/barrier layer3/insulating layer 13/upper electrode layer 14/upper shield layer 15 isprovided, D the portion where a lamination of lower shield layer11/lower electrode layer 12/free layer 2/barrier layer 3/pinned layer4/pinning layer 5/upper electrode layer 14/upper shield layer 15 isprovided, E the portion where a lamination of lower shield layer11/lower electrode layer 12/free layer 2/barrier layer 3/insulatinglayer 13/upper electrode layer 14/upper shield layer 15 is provided andF the portion where a lamination of lower shield layer 11/lowerelectrode layer 12/free layer 2/barrier layer 3/oxide/nitride layer1/upper electrode layer 14/upper shield layer 15 is provided.

[0063] With this magnetoresistive effect element, when it is assumedthat a current is caused to flow from the upper electrode layer 14 tothe lower electrode layer 12 in FIG. 1, the current flows from the upperelectrode layer 14 successively through the pinning layer 5, the pinnedlayer 4, the barrier layer 3 and the free layer 2 to the lower electrodelayer 12 and does not pass through any other current paths.

[0064] Although a description was given above for a structure such thatthe lower electrode layer 12 is deposited on the lower shield layer 11with the upper shield layer 15 being deposited on the upper electrodelayer 14, it is possible to provide as a gap layer an insulating layerbetween the lower shield layer 11 and the lower electrode layer 12 orbetween the upper electrode layer 14 and the upper shield layer 15. Thelower shield layer 11 and the lower electrode layer 12 or the upperelectrode layer 14 and the upper shield layer 15 may be combinedtogether. It is also possible to a provide an underlayer between thelower electrode layer 12 and the free layer 2 and/or an upper layerbetween the pinning layer 5 and the upper electrode layer 14.

[0065] Modifications of the above-described embodiment will now bedescribed with reference to FIGS. 2 to 12.

[0066]FIG. 2 is an illustration showing a modified magnetoresistiveeffect element in cross-section parallel to its ABS. In thisarrangement, a lower shield layer 11, a lower gap layer 21 and a lowerelectrode layer 12 are deposited on a substrate. Upon these layers, alamination of an underlayer (not shown)/free layer 2/barrier layer 3 isprovided. A lamination of a pinned layer 4/pinning layer 5/upper layer20/upper electrode layer 14 is provided on the lamination of theunderlayer/free layer 2/barrier layer 3 between right and leftlongitudinal biasing layers 6 and is patterned as shown in FIG. 2. Anoxide or nitride layer 1 (i.e., oxide or nitride of metallic materialsconstituting the pinned and pinning layers 4 and 5) is formed on theside walls of the patterned lamination of pinned layer 4/pinning layer5. Insulating layers 13 are further provided on the right and left sidesof the layers 1. An upper electrode layer 14, an upper gap layer 22 andan upper shield layer 15 are deposited on these layers.

[0067] The portion constituted by the lamination of the underlayer/freelayer 2/barrier layer 3/pinned layer 4/pinning layer 5 corresponds to anMTJ film.

[0068] With this structure, when it is assumed that a current is causedto flow from the upper electrode layer 14 to the lower electrode layer12 in FIG. 2, the current flows from the upper electrode layer 14successively through the pinning layer 5, the pinned layer 4, thebarrier layer 3 and the free layer 2 to the lower electrode layer 12 anddoes not pass through any other current paths.

[0069] It should be noted that the lower gap layer 21, the upper gaplayer 22, the lower electrode layer 12, the upper electrode layer 14,the underlayer of the free layer 3 and/or the upper layer 20 may bedispensed with.

[0070]FIG. 3 shows another structure which is similar to the structureshown in FIG. 2 but the lower gap layer 21 and the upper gap layer 22have been omitted.

[0071]FIG. 4 shows a further structure which is similar to the structureshown in FIG. 2 but the upper electrode layer 14 has further beenomitted, that is to say, the upper electrode layer 14 has been combinedwith the upper shield layer 15. In this arrangement, the upper layer 20of FIG. 2 has been omitted and instead a protective layer 24 has beenformed.

[0072]FIG. 5 shows a further structure which is similar to the structureof FIG. 4 but the lamination of the underlayer/free layer 2 is formedalso on the pattern of the longitudinal biasing layers 6 and on the endfaces thereof.

[0073]FIG. 6 shows a further structure which is similar to the structureshown in FIG. 4 but the oxide/nitride layer 1 is formed also on thebarrier layer 3. More specifically, the oxide/nitride layer 1 is formedon the side faces of the pattern of the pinned layer 4, pinning layer 5and protective layer 24 and upper portions of the barrier layer 3. Inpractice, the oxide/nitride layer 1 is formed, for example, by havingthe pinned layer 4 remain on the barrier layer 3 and then oxidizingthem. In that case, the side faces of the pinned layer 4, pinning layer5 and protective layer 24 are also oxidized. Metallic materialsredeposited on the side faces of the pinned layer 4, pinning layer 5 andprotective layer 24 during the patterning process are thus oxidized.Although the oxide/nitride layer 1 is formed also on the longitudinalbiasing layer 6 in this example as shown in FIG. 6, this may bedispensed with. The oxide/nitride layer 1 does not necessarily have tobe formed entirely on the side faces of the pinned layer 4, pinninglayer 5 and protective layer 24 but may be formed only on a part of theside faces. Furthermore, the protective layer 24 and the underlayer ofthe free layer 2 may be omitted.

[0074]FIG. 7 shows a modification of the structure shown in FIG. 6. Theoxide/nitride layer 1 formed on the barrier layer 3 as well as thelongitudinal biasing layers 6 does not necessarily have to havesubstantially the same film thickness as the pinned layer 4 but may havea film thickness which is significantly different from that of thepinned layer 4 as shown. Also, the oxide/nitride layer 1 on the barrierlayer 3 does not necessarily have to be made of an oxide or nitride ofthe metallic materials constituting the pinned layer 4 but may containan oxide or nitride of the metallic materials constituting the pinninglayer 5 and/or upper layer 20 formed thereon.

[0075]FIG. 8 shows another modification of the structure shown in FIG.6, in which the oxide/nitride layer 1 is formed not only on the sidefaces of the lamination of pinned layer 4/pinning layer 5/upper layer 20but also on the barrier layer 3 in the vicinity of the pattern of pinnedlayer 4/pinning layer 5/upper layer 20. This structure corresponds tothe case where the oxide/nitride layer 1 is formed by later oxidizingthe portion of the pinned layer 4 which has been left on the barrierlayer 3 in the vicinity of the pattern of pinned layer 4/pinning layer5/upper layer 20 in the patterning process.

[0076]FIG. 9 shows a modification of the structure shown in FIG. 7,wherein the oxide/nitride layer 1 is formed also on the slopes of thelongitudinal biasing layers 6.

[0077]FIG. 10 shows another structure in which the oxide/nitride layer 1is formed on the side faces of the lamination of free layer 2/barrierlayer 3/pinned layer 4/pinning layer 5/protective layer 24 as well as onthe lower electrode layer 12. This structure corresponds to the casewhere the oxide/nitride layer 1 is formed by later oxidizing the freelayer 2 which has been left in the patterning process. Although theoxide/nitride layer 1 is not formed on the pattern of the longitudinalbiasing layers 6 in this example as shown in FIG. 10, the layer 1 may beformed on the layers 6. Also, the shown example has no oxide/nitridelayer 1 formed on the slopes of the pattern of the longitudinal biasinglayers 6, but the layer 1 may be formed on the slopes.

[0078]FIG. 11 shows a further structure in which the oxide/nitride layer1 is formed on the side faces of the lamination of free layer 2/barrierlayer 3/pinned layer 4/pinning layer 5/protective layer 24 as well as onthe free layer 2. This structure corresponds to the case where theoxide/nitride layer 1 is formed by later oxidizing the upper portion ofthe free layer 2 which has been left in the patterning process. Althoughthe oxide/nitride layer 1 is formed on the pattern of the longitudinalbiasing layers 6 in this example as shown in FIG. 11, the layer 1 maynot be formed on the layers 6. Also, the shown example has nooxide/nitride layer 1 formed on the slopes of the pattern of thelongitudinal biasing layers 6, but the layer 1 may be formed on theslopes.

[0079]FIG. 12 shows a further structure in which the lamination of thefree layer 2/barrier layer 3/pinned layer 4/pinning layer 5/upper layer20 is patterned and in which the oxide/nitride layer 1 is formed on theends of the pattern. In this case, it is optional whether the underlayerof the free layer 2 is patterned or not, and the underlayer of the freelayer 2 may be left on the lower electrode layer 12. The free layer 2may be left on the patterns of the longitudinal biasing layers 6 and/orthe ends of these patterns. This example is shown to have such astructure that the lower shield layer 11 is combined with the lowerelectrode layer 12, wherein a gap adjusting conductive layer 25 isformed on the combined layer.

[0080] In the arrangements shown in FIGS. 4 to 12, the free layer 2 hasits underlayer, but such underlayer may be dispensed with.

[0081] [Second Embodiment]

[0082]FIG. 13 shows a magnetoresistive effect element according to thesecond embodiment in cross-section parallel to its ABS.

[0083] In this arrangement, a lower shield layer 11, a lower electrodelayer 12 and a free layer 2 are deposited in sequence on a substrate(not shown). Deposited upon these layers is a longitudinal biasing layer6 which is patterned as shown in FIG. 13. A barrier layer 3, a pinnedlayer 4, a pinning layer 5 and an upper electrode layer 14 are depositedin sequence on the free layer 2 between the right and left longitudinalbiasing layers 6, and the layers 3, 4, 5 and 14 are then patterned asshown in FIG. 13. Furthermore, insulating layers 13 are provided on theright and left sides of these layers. The portion constituted by thelamination of the free layer 2/barrier layer 3/pinned layer 4/pinninglayer 5 corresponds to an MTJ film. An oxide/nitride layer 1 (a layercomposed of an oxide/nitride of the metallic materials constituting thepinned and pinning layers 4 and 5) is formed on side walls of thepatterned lamination of the pinned layer 4/pinning layer 5.

[0084]FIG. 20 is a plan view of the above magnetoresistive effectelement. In FIG. 20, shown at A is the portion where a lamination of thelower shield layer 11/lower electrode layer 12 is provided. Similarly, Brepresents the portion where a lamination of the lower shield layer11/lower electrode layer 12/free layer 2/insulating layer 13 isprovided; C the portion where a lamination of the lower shield layer11/lower electrode layer 12/free layer 2/longitudinal biasing layers6/insulating layer 13/upper shield layer 15 is provided; D the portionwhere a lamination of the lower shield layer 11/lower electrode layer12/free layer 2/barrier layer 3/pinned layer 4/pinning layer 5/upperelectrode layer 14/upper shield layer 15 is provided; E the portionwhere a lamination of the lower shield layer 11/lower electrode layer12/free layer 2/insulating layer 13/upper shield layer 15 is provided; Fthe portion where a lamination of the lower shield layer 11/lowerelectrode layer 12/free layer 2/insulating layer 13/upper electrodelayer 14/upper shield layer 15 is provided; G the portion where alamination of the lower shield layer 11/lower electrode layer 12/freelayer 2/insulating layer 13/upper electrode layer 14 is provided; H theportion where a lamination of the lower shield layer 11/lower electrodelayer 12/free layer 2/insulating layer 13/upper shield layer 15 isprovided; and I the portion where a lamination of the lower shield layer11/lower electrode layer 12/free layer 2/oxide/nitride layer 1/upperelectrode layer 14/upper shield layer 15 is provided.

[0085] With this magnetoresistive effect element, when it is assumedthat a current is caused to flow from the upper electrode layer 14 tothe lower electrode layer 12 in FIG. 13, the current flows from theupper electrode layer 14 sequentially through the pinning layer 5, thepinned layer 4, the barrier layer 3 and the free layer 2 to the lowerelectrode layer 12 and does not pass through any other current paths.

[0086] Although a description was given above for a structure such thatthe lower electrode layer 12 is deposited on the lower shield layer 11,it is possible to provide an insulating layer between the lower shieldlayer 11 and the lower electrode layer 12 as a gap layer. It is alsopossible to combine the lower shield layer 11 and the lower electrodelayer 12 together. It is further possible to provide an underlayerbetween the lower electrode layer 12 and the free layer 2.

[0087] [Third Embodiment]

[0088]FIG. 14 illustrates a magnetoresistive effect element according tothe third embodiment in cross-section parallel to its ABS.

[0089] In this arrangement, a lower shield layer 11 and a lowerelectrode layer 12 are deposited in sequence on a substrate (not shown).Upon these layers, a pinning layer 5, a pinned layer 4, a barrier layer3 and a free layer 2 are sequentially deposited and patterned as shownin FIG. 14. An oxide/nitride layer 1 (i.e., a layer composed of oxide ornitride of the metallic materials which constitute the pinning layer 5,pinned layer 4, barrier layer 3 and free layer 2) is formed on sidewalls of the lamination of the pinning layer 5/pinned layer 4/barrierlayer 3/free layer 2. Insulating layers 13 are further provided outsidethe layer 1. Longitudinal biasing layers 6 are provided on the right andleft sides of the free layer 2. Upon these layers, an upper electrodelayer 14 and an upper shield layer 15 are sequentially deposited. Theportion constituted by the lamination of the pinning layer 5/pinnedlayer 4/barrier layer 3/free layer 2 corresponds to an MTJ film.

[0090]FIG. 21 is a plan view of the above magnetoresistive effectelement. In FIG. 21, shown at A is the portion where a lamination of thelower shield layer 11/lower electrode layer 12 is provided. In a similarmanner, B represents the portion where a lamination of the lower shieldlayer 11/lower electrode layer 12/insulating layer 13 is provided; C theportion where a lamination of the lower shield layer 11/lower electrodelayer 12/longitudinal biasing layer 6/upper electrode layer 14/uppershield layer 15 is provided; D the portion where a lamination of thelower shield layer 11/lower electrode layer 12/pinning layer 5/pinnedlayer 4/barrier layer 3/free layer 2/upper electrode layer 14/uppershield layer 15 is provided; E the portion where a lamination of thelower shield layer 11/lower electrode layer 12/insulating layer 13/upperelectrode layer 14/upper shield layer 15 is provided and F the portionwhere a lamination of the lower shield layer 11/lower electrode layer12/pinning layer 5/pinned layer 4/barrier layer 3/free layer2/oxide/nitride layer 1/insulating layer 13/longitudinal biasing layer6/upper electrode layer 14/upper shield layer 15 is provided.

[0091] With this magnetoresistive effect element, when it is assumedthat a current is caused to flow from the upper electrode layer 14 tothe lower electrode layer 12 in FIG. 14, the current flows from theupper electrode layer 14 successively through the free layer 2, thebarrier layer 3, the pinned layer 4 and the pinning layer 5 to the lowerelectrode layer 12 and does not pass through any other current paths.

[0092] Although a description was given above for a structure such thatthe lower electrode layer 12 is deposited on the lower shield layer 11with the upper shield layer 15 being deposited on the upper electrodelayer 14, it is possible to provide as a gap layer an insulating layerbetween the lower shield layer 11 and the lower electrode layer 12 orbetween the upper electrode layer 14 and the upper shield layer 15. Itis also possible to combine the lower shield layer 11 with the lowerelectrode layer 12 or the upper electrode layer 14 with the upper shieldlayer 15. It is further possible to provide an underlayer between thelower electrode layer 12 and the pinning layer 5 and/or an upper layerbetween the free layer 2 and the upper electrode layer 14. Although thelamination of pinning layer 5/pinned layer 4/barrier layer 3/free layer2 of the MTJ film is patterned in the shown example, it is sufficientthat at least the free layer 2 of the MTJ film is patterned, and it isoptional which one of those layers of the MTJ film below the free layer2 the MTJ film should be patterned.

[0093]FIG. 15 shows a modification of the structure shown in FIG. 14.The structure of this modification is different from that shown in FIG.14 in that the longitudinal biasing layers 6 extend over the free layer2 with the protective layer 24 interposed therebetween. In this case,the protective layer 24 may be omitted.

[0094] [Fourth Embodiment]

[0095]FIG. 16 illustrates a magnetoresistive effect element according tothe fourth embodiment in cross-section parallel to its ABS.

[0096] In this arrangement, a lower shield layer 11 and a lowerelectrode layer 12 are deposited in sequence on a substrate (not shown).Upon these layers, a pinning layer 5, a pinned layer 4, a barrier layer3 and a free layer 2 are sequentially deposited and patterned as shownin FIG. 16. An oxide/nitride layer 1 (i.e., a layer composed of oxide ornitride of the metallic materials which constitute the pinning layer 5,pinned layer 4, barrier layer 3 and free layer 2) is formed on the sidewalls of the lamination of the pinning layer 5/pinned layer 4/barrierlayer 3/free layer 2. Longitudinal biasing layers 6 composed of aninsulating material are further provided outside the layers 1. Uponthese layers, an upper electrode layer 14 and an upper shield layer 15are sequentially deposited. The portion constituted by the lamination ofthe pinning layer 5/pinned layer 4/barrier layer 3/free layer 2corresponds to an MTJ film.

[0097] With this arrangement, when it is assumed that a current iscaused to flow from the upper electrode layer 14 to the lower electrodelayer 12 in FIG. 16, the current flows from the upper electrode layer 14successively through the free layer 2, the barrier layer 3, the pinnedlayer 4 and the pinning layer 5 to the lower electrode layer 12 and doesnot pass through any other current paths.

[0098]FIG. 22 is a plan view of the above magnetoresistive effectelement. In FIG. 22, shown at A is the portion where a lamination of thelower shield layer 11/lower electrode layer 12 is provided. In a similarmanner, B represents the portion where a lamination of the lower shieldlayer 11/lower electrode layer 12/insulating layer 13 is provided; C theportion where a lamination of the lower shield layer 11/lower electrodelayer 12/longitudinal biasing layer 6/upper electrode layer 14/uppershield layer 15 is provided; D the portion where a lamination of thelower shield layer 11/lower electrode layer 12/pinning layer 5/pinnedlayer 4/barrier layer 3/free layer 2/upper electrode layer 14/uppershield layer 15 is provided; E the portion where a lamination of thelower shield layer 11/lower electrode layer 12/insulating layer 13/upperelectrode layer 14/upper shield layer 15 is provided; and F the portionwhere a lamination of the lower shield layer 11/lower electrode layer12/pinning layer 5/pinned layer 4/barrier layer 3/free layer2/oxide/nitride layer 1/longitudinal biasing layer 6/upper electrodelayer 14/upper shield layer 15 is provided.

[0099] Although a description was given above for a structure such thatthe lower electrode layer 12 is deposited on the lower shield layer 11with the upper shield layer 15 being deposited on the upper electrodelayer 14, it is possible to provide as a gap layer an insulating layerbetween the lower shield layer 11 and the lower electrode layer 12 orbetween the upper electrode layer 14 and the upper shield layer 15. Itis also possible to combine the lower shield layer 11 with the lowerelectrode layer 12 or the upper electrode layer 14 with the upper shieldlayer 15. It is further possible to provide an underlayer between thelower electrode layer 12 and the pinning layer 5 and/or an upper layerbetween the free layer 2 and the upper electrode layer 14. Although thelamination of pinning layer 5/pinned layer 4/barrier layer 3/free layer2 of the MTJ film is patterned in the shown example, it is sufficientthat at least the free layer 2 of the MTJ film is patterned, and it isoptional which one of those layers of the MTJ film below the free layer2 the MTJ film should be patterned.

[0100] [Fifth Embodiment]

[0101]FIG. 17 illustrates a magnetoresistive effect element according tothe fifth embodiment in cross-section parallel to its ABS.

[0102] In this arrangement, a lower shield layer 11 and a lowerelectrode layer 12 are deposited in sequence on a substrate (not shown).Upon these layers, a pinning layer 5, a pinned layer 4, a barrier layer3, a free layer 2, an interface control layer 7 and a longitudinalbiasing layer 6 are sequentially deposited and patterned as shown inFIG. 17. A longitudinal bias is applied to the free layer 2 after itsmagnitude has been controlled by the interface control layer 7. Anoxide/nitride layer 1 (i.e., a layer composed of oxide or nitride of themetallic materials which constitute the pinning layer 5, pinned layer 4,barrier layer 3, free layer 2, interface control layer 7 andlongitudinal biasing layer 6) is formed on side walls of the laminationof the pinning layer 5/pinned layer 4/barrier layer 3/free layer2/interface control layer 7/longitudinal biasing layer 6. Insulatinglayers 13 are further provided outside the layers 1. Upon these layers,an upper electrode layer 14 and an upper shield layer 15 aresequentially deposited. The portion constituted by the lamination of thepinning layer 5/pinned layer 4/barrier layer 3/free layer 2 correspondsto an MTJ film.

[0103]FIG. 23 is a plan view of the above magnetoresistive effectelement. In FIG. 23, shown at A is the portion where a lamination of thelower shield layer 11/lower electrode layer 12 is provided. In a similarmanner, B represents the portion where a lamination of the lower shieldlayer 11/lower electrode layer 12/insulating layer 13 is provided; C theportion where a lamination of the lower shield layer 11/lower electrodelayer 12/insulating layer 13/upper electrode layer 14/upper shield layer15 is provided; D the portion where a lamination of the lower shieldlayer 11/lower electrode layer 12/pinning layer 5/pinned layer 4/barrierlayer 3/free layer 2/interface control layer 7/longitudinal biasinglayer 6/upper electrode layer 14/upper shield layer 15 is provided; andE the portion where a lamination of the lower shield layer 11/lowerelectrode layer 12/pinning layer 5/pinned layer 4/barrier layer 3/freelayer 2/interface control layer 7/longitudinal biasing layer6/oxide/nitride layer 1/upper electrode layer 14/upper shield layer 15is provided.

[0104] With this arrangement, when it is assumed that a current iscaused to flow from the upper electrode layer 14 to the lower electrodelayer 12 in FIG. 17, the current flows from the upper electrode layer 14successively through the longitudinal biasing layer 6, the interfacecontrol layer 7, the free layer 2, the barrier layer 3, the pinned layer4 and the pinning layer 5 to the lower electrode layer 12 and does notpass through any other current paths.

[0105] Although a description was given above for a structure such thatthe lower electrode layer 12 is deposited on the lower shield layer 11with the upper shield layer 15 being deposited on the upper electrodelayer 14, it is possible to provide as a gap layer an insulating layerbetween the lower shield layer 11 and the lower electrode layer 12 orbetween the upper electrode layer 14 and the upper shield layer 15. Itis also possible to combine the lower shield layer 11 with the lowerelectrode layer 12 or the upper electrode layer 14 with the upper shieldlayer 15. It is further possible to provide an underlayer between thelower electrode layer 12 and the pinning layer 5 and/or an upper layerbetween the longitudinal biasing layer 6 and the upper electrode layer14. The interface control layer 7 can be omitted by selecting a suitablematerial for the longitudinal biasing layer 6. Although the laminationof the pinning layer 5/pinned layer 4/barrier layer 3/free layer 2 ofthe MTJ film 8 is patterned in the shown example, it is sufficient thatat least the free layer 2 of the MTJ film is patterned, and it isoptional which one of those layers of the MTJ film below the free layer2 the film should be patterned.

[0106] [Sixth Embodiment]

[0107]FIG. 18 illustrates a magnetoresistive effect element according tothe sixth embodiment in cross section parallel to its ABS.

[0108] In this example, a lower shield layer 11 which also serves as alower electrode layer 12 is deposited on a substrate (not shown). A gapadjustment conductive layer 25 is deposited on the layer 11, and alamination of an underlayer (not shown)/pinning layer 5/pinned layer4/barrier layer 3/free layer 2/protective layer 24 is further providedon the layer 25 and patterned. The lamination of the underlayer/pinninglayer 5/pinned layer 4/barrier layer 3/free layer 2/protective layer 24constitutes an MTJ film. An oxide/nitride layer 1 is formed on sidewalls of the pattern of the MTJ film. An insulating layer 13 is providedon the right and left sides of the layers 1. Longitudinal biasing layers6 are formed on the right and left sides of the MTJ film with theinsulating layer 13 interposed therebetween. The insulating layer 13lies between the pattern of the longitudinal biasing layers 6 and thecombination of the lower shield layer 11 with the lower electrode layer12 and between the longitudinal biasing layers 6 and the combination ofan upper electrode layer 14 with an upper shield layer 15. Upon theselayers, the upper electrode layer 14 which is adapted to serve also asthe upper shield layer 15 is further deposited.

[0109] In this example, the lower shield layer 11 and the lowerelectrode layer 12 and/or the upper electrode layer 14 and the uppershield layer 15 may be combined, or may also be provided separately. Anupper gap layer may be provided between the upper electrode layer 14 andthe upper shield layer 15, and a lower gap layer may be provided betweenthe lower shield layer 11 and the lower electrode layer 12. Theunderlayer of the pinning layer 5 and the protective layer 24 on thefree layer 2 may be omitted. Although the lamination of theunderlayer/pinning layer 5/pinned layer 4/barrier layer 3/free layer2/protective layer 24 is patterned in this example, it is optional up towhich one of these layers the lamination is patterned.

[0110] The description was given above for the case that eachlongitudinal biasing layer has a rectangular shape when viewed from thetop as shown in FIGS. 19 to 23, but these layers may take various othershapes.

[0111] A description will now be given in detail on each of thestructures and representative examples of the manufacturing processestherefor. Some examples of applications to recording/reproducing headswill also be described.

[0112] Hereinafter, examples of materials useful for each layer will begiven.

[0113] AlTiC, SiC, alumina, AlTiC/alumina and Sic/alumina are given asexamples of the materials for the substrate 10.

[0114] A simple substance, a multilayer film or a mixture comprisingNiFe, CoZr, CoFeD, CoZrMo, CoZrNb, CoZr, CoZrTa, CoHf, CoTa, CoTaHf,CoNbHf, CoZrNb, CoHfPd, CoTaZrNb or CoZrMoNi alloy, FeAlSi, iron-nitridegroup material, MnZn ferrite, NiZn ferrite or MgZn ferrite may be usedfor the lower shield layer 11.

[0115] A simple substance, a multilayer film or a mixture comprising Au,Ag, Cu, Mo, W, Y, Ti, Zr, Hf, V, Nb, Pt or Ta may be used for the lowerelectrode layer 12.

[0116] A simple substance, a multilayer film or a mixture comprising Aloxide, silicon oxide, aluminum nitride, silicon nitride, diamond-likecarbon, Au, Ag, Cu, Mo, W, Y, Ti, Zr, Hf, V, Pt, Nb or Ta may be usedfor the interface control layer 7.

[0117] A simple substance, a multilayer film or a mixture comprising Au,Ag, Cu, Mo, W, Y, Pt, Ti, Zr, Hf, V, Nb or Ta may be used for the upperelectrode layer 14.

[0118] A simple substance, a multilayer film or a mixture comprisingNiFe, CoZr, CoFeB, CoZrMo, CoZrNb, CoZr, CoZrTa, CoHf, CoTa, CoTaHf,CoNbHf, CoZrNb, CoHfPd, CoTaZrNb or CoZrMoNi alloy, FeAlSi, iron-nitridegroup material, MnZn ferrite, NiZn ferrite or MgZn ferrite may be usedfor the upper shield layer 15.

[0119] A simple substance, a multilayer film or a mixture comprisingaluminum oxide, silicon oxide, aluminum nitride, silicon nitride ordiamond-like carbon may be used for the insulating layer 13.

[0120] A simple substance, a multilayer film or a mixture comprising Aloxide, silicon oxide, aluminum nitride, silicon nitride or diamond-likecarbon may be used for the lower gap layer 21 and/or the upper gap layer22.

[0121] A simple substance, a multilayer film or a mixture comprising Au,Ag, Cu, Mo, W, Y, Ti, Pt, Zr, Hf, V, Nb or Ta may be used for the upperlayer 20.

[0122] A simple substance, a multilayer film or a mixture comprisingCoCrPt, CoCr, CoPt, CoCrTa, FeMn, NiMn, Ni oxide, NiCo oxide, Fe oxide,NiFe oxide, IrMn, PtMn, PtPdMn, ReMn, Co ferrite or Ba ferrite may beused for the longitudinal biasing layer 6.

[0123] The following structures can be used for the MTJ film(magnetoresistive effect film):

[0124] A first structure may comprise a lamination of asubstrate/underlayer/free layer/first MR enhancement layer/barrierlayer/second MR enhancement layer/pinned layer/pinning layer/protectivelayer;

[0125] A second structure may comprise a lamination of asubstrate/underlayer/pinning layer/pinned layer/first MR enhancementlayer/barrier layer/second MR enhancement layer/free layer/protectivelayer;

[0126] A third structure may comprise a lamination of asubstrate/underlayer/first pinning layer/first pinned layer/first MRenhancement layer/barrier layer/second MR enhancement layer/freelayer/third MR enhancement layer/barrier layer/fourth MR enhancementlayer/second pinned layer/second pinning layer/protective layer;

[0127] A fourth structure may comprise a lamination of asubstrate/underlayer/pinning layer/first MR enhancement layer/barrierlayer/second MR enhancement layer/free layer/protective layer; and

[0128] A fifth structure may comprise a lamination of asubstrate/underlayer/free layer/first MR enhancement layer/barrierlayer/second MR enhancement layer/pinned layer/protective layer.

[0129] For the underlayer, a single layer film, a film of mixture or amultilayer film comprising a metal, an oxide and/or a nitride is used.More specifically, use is made of a single layer film, a film of mixtureor a multilayer film comprising Ta, Hf, Zr, W, Cr, Ti, Mo, Pt, Ni, Ir,Cu, Ag, Co, Zn, Ru, Rh, Re, Au, Os, Pd, Nb, V or an oxide or nitride ofany one of these materials. Furthermore, Ta, Hf, Zr, W, Cr, Ti, Mo, Pt,Ni, Ir, Cu, Ag, Co, Zn, Ru, Rh, Re, Au, Os, Pd, Nb and/or V can be usedas an additive element. There may be cases where the underlayer isomitted as described before.

[0130] For the free layer 2, NiFe, CoFe, NiFeCo, FeCo, CoFeB, CoZrMo,CoZrNb, CoZr, CoZrTa, CoHf, CoTa, CoTaHf, CoNbHf, CoZrNb, CoHfPd,CoTaZrNb or CoZrMoNi alloy or an amorphous magnetic material may beused.

[0131] For the barrier layer 3, an oxide, a nitride, a mixture of oxideand nitride, a two-layer film of metal/oxide, a two-layer film ofmetal/nitride or a two-layer film of metal/a mixture of oxide andnitride is used. Potential candidates may be a simple substance, amultilayer film or a mixture of oxide or nitride of Ti, V, Cr, Co, Cu,Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, Au,Si, Al, Ti, Ta, Pt, Ni, Co, Re or V, or a film formed by laminating anyone of these and a simple substance, a multilayer film or a mixture ofoxide or nitride of Ti, V, Cr, Co, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh,Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, Au, Si, Al, Ti, Ta, Pt, Ni, Co, Re orV.

[0132] For the first and/or the second MR enhancement layer, Co, NiFeCoor FeCo; or CoFeB, CoZrMo, CoZrNb, CoZr, CoZrTa, CoHf, CoTa, CoTaHf,CoNbHf, CoZrNb, CoHfPd, CoTaZrNb or CoZnMoNi alloy or an amorphousmagnetic material is used. When the MR enhancement layer is not used,the MR ratio will be slightly lower than when such layer is used but thenumber of processes required for the manufacture will be decreased.

[0133] For the pinned layer 4, NiFe, CoFe, NiFeCo, FeCo, CoFeB, CoZrMo,CoZrNb, CoZr, CoZrTa, CoHf, CoTa, CoTaHf, CoNbHf, CoZrNb, CoHfPd,CoTaZrNb or CoZrMoNi alloy or an amorphous magnetic material may beused. It is also possible to use a film formed by laminating any ofthese materials and a simple substance, an alloy or a laminated filmcomposed of a group containing as a base Ti, V, Cr, Co, Cu, Zn, Y, Zr,Nb, Mo, Tc, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, Au, Si, Al, Ti,Ta, Pt, Ni, Co, Re or V. Potential candidates may be a lamination ofCo/Ru/Co, CoFe/Ru/CoFe, CoFeNi/Ru/CoFeNi, Co/Cr/Co, CoFe/Cr/CoFe orCoFeNi/Cr/CoFeNi.

[0134] For the pinning layer 5, for example, FeMn, NiMn, IrMn, RhMn,PtPdMn, ReMn, PtMn, PtCrMn, CrMn, CrAl, TbCo, Ni oxide, Fe oxide, amixture of Ni oxide and Co oxide, a mixture of Ni oxide and Fe oxide, atwo-layer film of Ni oxide/Co oxide, a two-layer film of Ni oxide/Feoxide, CoCr, CoCrPt, CoCrTa or PtCo can be used. A material comprisingPtMn, or PtMn to which Ti, V, Cr, Co, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh,Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, Au, Si, Al, Ti or Ta is added may bea potential candidate.

[0135] For the protective layer 24, an oxide, a nitride, a mixture ofoxide and nitride, a two-layer film of metal and oxide, a two-layer filmof metal/nitride or a two-layer film of metal/a mixture of oxide andnitride is used. A simple substance, a multilayer film or a mixture ofoxide and/or nitride of Ti, V, Cr, Co, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru,Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, Au, Si, Al, Ti, Ta, Pt, Ni, Co,Re or V, or a film formed by laminating any of these materials and asimple substance, a multilayer film and a mixture of oxide or nitride ofTi, V, Cr, Co, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Hf, Ta, W, Re,Os, Ir, Pt, Au, Si, Al, Ti, Ta, Pt, Ni, Co, Re or V may be a potentialcandidate. There may be cases where the upper layer 20 is not used.

[0136] Examples of processes for manufacturing the magnetoresistiveeffect elements according to the first to sixth embodiments will now bedescribed with reference to FIGS. 24 to 27.

[0137]FIGS. 24A to 24I show, by way of example, a process formanufacturing the magnetoresistive effect element according to the firstembodiment, wherein the element is manufactured in sequential steps (1)to (9).

[0138] First, the lower shield layer 11 and the lower electrode layer 12are formed in sequence on the substrate 10 (step (1) in FIG. 24A).

[0139] A stencil PR 21 is formed on the layer 12 (step (2) in FIG. 24B),and the longitudinal biasing layer 6 is formed and lifted off (step (3)in FIG. 24C). The MTJ film (designated by reference numeral 8) and theupper electrode layer 14 are further formed (step (4) in FIG. 24D), onwhich a PR 22 is formed and then subjected to milling (step (5) in FIG.24E). Subsequently, the side walls of the patterned MTJ film 8 areoxidized or nitrided (step (6) in FIG. 24F). For the oxidation, use canbe made of a method in which spontaneous oxidization is caused to occurin the air, in an atmosphere of oxygen diluted by inert elements or inan oxygen atmosphere at a reduced pressure, or of a method in which aplasma is generated in an atmosphere of oxygen diluted by inert elementsat an adjusted pressure to thereby place the element in question incontact with the plasma (plasma oxidizing method). For the nitridation,a method in which a plasma is generated in an atmosphere of nitrogendiluted by an inert gas at an adjusted pressure to thereby place theelement in question in contact with the plasma can suitably be used. Itis also possible to oxidize or nitride the side walls of the MTJ film 8,during the time when the milling is being carried out, by introducing asuitable amount of oxygen or nitrogen in the milling gas. After theoxidization or nitridation step has been completed, the insulating layer13 is formed and then lifted off (step (7) in FIG. 24G). A recess isformed in the insulating layer 13 down to such a level that the lowerelectrode is exposed (step (8) in FIG. 24H) and the upper shield layer15 is then formed (step (9) in FIG. 24I).

[0140]FIGS. 25A to 25H show, by way of example, a process formanufacturing the magnetoresistive effect element according to thesecond embodiment, wherein the element is manufactured in sequentialsteps (1) to (8).

[0141] First, the lower shield layer 11, the lower electrode layer 12,the MTJ film 8 and the upper electrode layer 14 are sequentially formedon the substrate 10 (step (1) in FIG. 25A). A stencil PR 21 is formed onthe layer 14 and then subjected to milling (step (2) in FIG. 25B).Subsequently, the side walls of the patterned MTJ film 8 are oxidized ornitrided (step (3) in FIG. 25C). For the oxidation, use can be made of amethod in which spontaneous oxidization is caused to occur in air, in anatmosphere of oxygen diluted by inert elements or in an oxygenatmosphere at a lowered pressure, or of a method in which a plasma isgenerated in an atmosphere of oxygen diluted by inert elements at anadjusted pressure to thereby make the element in question contact theplasma (plasma oxidizing method). For the nitridation, a method in whicha plasma is generated in an atmosphere of nitrogen diluted by an inertgas at an adjusted pressure to make the element in question contact theplasma can suitably be used. It is also possible to oxidize or nitridethe side walls of the MTJ film 8, during the time when the milling isbeing carried out, by introducing a suitable amount of oxygen ornitrogen in the milling gas. After the oxidization or nitridation stephas been completed, the stencil PR 21 is removed. A PR 22 is furtherformed (step (4) in FIG. 25D), and the longitudinal biasing layer 6 isformed and lifted off (step (5) in FIG. 25E). Subsequently, theinsulating layer 13 is formed and then shaved by means ofchemical-mechanical polishing (CMP) down to a level where the upperelectrode layer 14 is exposed (step (6) in FIG. 25F). A recess is formedin the insulating layer 13 down to such a depth that the lower electrodelayer 12 is exposed (step (7) in FIG. 25G) and then the upper shieldlayer 15 is formed (step (8) in FIG. 25H).

[0142]FIGS. 26A to 26H show, by way of example, a process formanufacturing the magnetoresistive effect element according to the thirdembodiment, wherein the element is manufactured in sequential steps (1)to (8).

[0143] First, the lower shield layer 11, the lower electrode layer 12and the MTJ film 8 are sequentially formed on the substrate 10 (step (1)in FIG. 26A). A stencil PR 21 is formed thereon (step (2) in FIG. 26B)and then subjected to milling (step (3) in FIG. 26C), whereafter theinsulating layer 13 and the longitudinal biasing layer 6 aresequentially formed and lifted off (step (4) in FIG. 26D). A PR 22 isthen formed and subjected to milling (step (5) in FIG. 26E) andsubsequently end portions of the patterned MTJ film are oxidized ornitrided (step (6) in FIG. 26F). For the oxidation, use can be made of amethod in which spontaneous oxidization is caused to occur in the air,in an atmosphere of oxygen diluted by inert elements or in an oxygenatmosphere at a lowered pressure, or of a method in which a plasma isgenerated in an atmosphere of oxygen diluted by inert elements at anadjusted pressure to thereby make the element in question contact theplasma (plasma oxidizing method). For the nitridation, a method in whicha plasma is generated in an atmosphere of nitrogen diluted by an inertgas at an adjusted pressure to make the element in question contact theplasma can suitably be used. It is also possible to oxidize or nitridethe side walls of the MTJ film, during the time when the milling isbeing carried out, by introducing a suitable amount of oxygen ornitrogen in the milling gas. After the oxidization or nitridation stephas been completed, the PR 22 is removed (step (6) in FIG. 26F). Arecess is formed in the insulating layer 13 down to such a depth thatthe lower electrode layer 12 is exposed (step (7) in FIG. 26G) and thenthe upper shield layer 15 is formed (step (8) in FIG. 26H).

[0144] The magnetoresistive effect element according to the fourthembodiment can be manufactured in a process similar to that describedabove for the third embodiment, and therefore a further description ofthis process will not be given herein.

[0145]FIGS. 27A to 27F show, by way of example, a process formanufacturing the magnetoresistive effect element according to the fifthembodiment, wherein the element is manufactured in sequential steps (1)to (6).

[0146] The lower shield layer 11, the lower electrode layer 12, the MTJfilm 8, the interface control layer 7 and the longitudinal biasing layer6 are sequentially formed on the substrate 10 (step (1) in FIG. 27A). Astencil PR 21 is formed thereon (step (2) in FIG. 27B) and thensubjected to milling, and thereafter the side walls of the patterned MTJfilm 8 are oxidized or nitrided (step (3) in FIG. 27C). For theoxidation, use can be made of a method in which spontaneous oxidizationis caused to occur in air, in an atmosphere of oxygen diluted by inertelements or in an oxygen atmosphere at a lowered pressure, or of amethod in which a plasma is generated in an atmosphere of oxygen dilutedby inert elements at an adjusted pressure to thereby make the element inquestion contact the plasma (plasma oxidizing method). For thenitridation, a method in which a plasma is generated in an atmosphere ofnitrogen diluted by an inert gas at an adjusted pressure to make theelement in question contact the plasma can suitably be used. It is alsopossible to oxidize or nitride the side walls of the MTJ film 8, duringthe time when the milling is being carried out, by introducing asuitable amount of oxygen or nitrogen in the milling gas. After theoxidization or nitridation step has been completed, the insulating layer13 is formed and then lifted off (step (4) in FIG. 27D). A recess isformed in the insulating layer 13 down to such a depth that the lowerelectrode layer 12 is exposed (step (5) in FIG. 27E), and the upperelectrode layer 14 and the upper shield layer 15 are formed (step (6) inFIG. 27F).

[0147] An example of application of the magnetoresistive effect elementaccording to the present invention to a magnetic recording/reproducinghead and a magnetic recording system will now be described.

[0148]FIG. 28 is an illustration schematically showing a magneticrecording/reproducing head to which the magnetoresistive effect elementaccording to the present invention is applied. This magneticrecording/reproducing head 130 is formed having, on a substrate 42, areproducing head 45 comprised of the magnetoresistive effect element anda recording head 46 comprised of a magnetic pole piece 43, a coil 41 andan upper magnetic pole piece 44. In this case, an upper shield film anda lower magnetic film may be combined or may be provided separately.With this head, a signal can be written onto a recording medium and readfrom the recording medium. The sensing portion of the reproducing headand the magnetic gap of the recording head are thus formed at overlappedpositions on the same slider, so that both heads can be positionedsimultaneously on the same track. This head is machined to form a sliderand mounted on a magnetic recording system.

[0149]FIG. 29 is a diagram showing a magnetoresistive conversion systemwhich comprises the magnetic recording/reproducing head shown in FIG.28. In this system, recording/reproducing element portions (magneticrecording/reproducing heads) 130 are formed on a substrate 129 servingas a slider, and are protected with a protective film 132. The substrate129 is composed of a composite ceramic such as Al₂O₃—TiO, and theprotective film 132 is composed of DLC (diamond-like carbon) as anexample.

[0150] An electrode terminal 131 a connecting to the recording elementportion (the magnetic recording head) and an electrode terminal 131 bconnecting to the reproducing element portion (the magnetic reproducinghead) are formed onto the recording/reproducing element portion 130. Theelectrode terminal 131 a is also connected to a current driving circuit133, which applies a drive current to the recording element portion forthe recording activity. The electrode terminal 131 b is also connectedto a current generating circuit 134 and a data reading circuit 135. Thecurrent generating circuit 134 makes a sense current flow through thereproducing element portion. On the other hand, the data reading circuit135 detects a voltage change due to a change in resistivity of thereproducing element portion as a function of a detected magnetic field,thereby reads out the recorded data onto a magnetic recording medium. Asstated above, the magnetoresistive conversion system comprises therecording/reproducing element portion 130, the current generatingcircuit 134 and the data reading circuit 135.

[0151]FIG. 30 is a diagrammatic illustration showing an example of amagnetic recording system which utilizes the magnetoresistive conversionsystem shown in FIG. 29. This magnetic recording system is formed havingthe magnetoresistive conversion system which comprises a magneticrecording/reproducing head 103, a magnetic recording medium 102 whichcomprises a plurality of tracks for data recording, a voice coil motor(hereinafter referred to as “VCM”; a first actuator) 103 which moves themagnetic recording/reproducing head 103 to a predetermined position onthe magnetic recording medium 102, and a motor 101 (a second actuator)which drives the magnetic recording medium 102 so as to rotate thismedium.

[0152] As shown in FIG. 30, the magnetic recording/reproducing head 103is attached to a suspension 104 and an arm 105, and is set to a positionto oppose the magnetic recording surface of the magnetic recordingmedium 102 rotated by the driving motor 101. The VCM 106 controls thetracking operation for the magnetic recording/reproducing head 103.Recording/reproducing activities are carried out based on the signaltransmitted from a recording/reproducing channel 107 to the magneticrecording/reproducing head 103. The recording/reproducing channel 107,the VCM 106 which performs the positioning of the head and the motor 101which rotates the magnetic recording medium 102 work together undercontrol of a control unit 108.

[0153]FIG. 31 shows a perspective view of a concrete example of themagnetic recording system. In this example, a magneticrecording/reproducing head 103 comprised of a reproducing head 51 and arecording head 50 is formed on a substrate 52 serving as a head slider,which is positioned on a magnetic recording medium 53 to carry outreproduction. The magnetic recording medium 53 rotates, while the headslider opposes the magnetic recording medium 53 and thus performs arelative movement thereto with a gap not greater than 0.2 μm or in acontacted condition. With this structure, the reproducing head 51 is setto such a position that a magnetic signal recorded on the magneticrecording medium 53 can be read from its leakage magnetic field 54.

[0154] Examples of the magnetoresistive effect element according to thepresent invention will now be described.

EXAMPLE 1

[0155] Example 1 corresponds to the magnetoresistive effect elementprovided in accordance with the first embodiment. An element having thestructure shown in FIG. 8 was produced. For the MTJ film, a laminationof Ta (3 nm)/Ni₈₂Fe₁₈ (5 nm)/Co₉₀Fe₁₀ (0.5 nm)/Al oxide (0.7nm)/Co₉₀Fe₁₀ (2 nm)/Ru (0.7 nm)/Co₉₀Fe₁₀ (2 nm)/Pt₄₆Mn₅₄ (15 nm)/Ta (3nm) was used. After the formation of the film, a heat treatment wascarried out at 250° C. for five hours with a magnetic field of 500 Oebeing applied in a direction perpendicular to that during the formationof the film. In the patterning process of the MTJ film in thisexperimental production of the element, the MTJ film was patterned bymeans of milling up to the middle of the pinned layer (Co₉₀Fe₁₀ (2nm)/Ru (0.7 nm)/Co₉₀Fe₁₀ (2 nm)). For the patterning of the MTJ film andthe oxidization of the end portions of the patterned MTJ film, use wasmade of a method of normal milling plus plasma oxidization. Morespecifically, the MTJ film was milled by means of a normal millingapparatus in a pure Ar-gas atmosphere at 0.3 Pa, whereafter the film wasmoved into a plasma oxidization apparatus (ashing apparatus) in whichthe end portions of the MTJ film and the milling residues on the pinnedlayer were oxidized. The conditions of the ashing process were such thatthe end portions of the MTJ film were in contact for twenty minutes witha plasma generated in an atmosphere containing 0.3 Pa of Ar and 0.1 Paof O₂ by supplying RF power at 200 W thereto.

[0156] For comparison with the above elements, further elements werealso manufactured on an experimental basis in which the plasmaoxidization process was omitted. For these elements, the followingsub-elements were used:

[0157] Substrate—A 2 nm thick AlTiC layer on which alumina is depositedwith a thickness of 10 μm;

[0158] Lower shield layer—A layer of Co₆₅Ni₁₂Fe₂₃ (composition expressedin atomic percent; same applies in the following description) of 1 μm inthickness;

[0159] Lower electrode layer—Ta (1.5 nm)/Pt (10 nm)/Ta (10 nm);

[0160] Upper electrode layer—Ta (1.5 nm)/Au (20 nm)/Ta (3 nm);

[0161] Upper shield layer—A layer of Co₈₉Zr₄Ta₄Cr₃ of 1 μm in thickness;

[0162] Insulating layer—A 40 nm thick alumina layer;

[0163] Longitudinal biasing layer—Cr (10 nm)/Co₇₄₅Cr_(10.5)Pt₁₅ (36 nm);

[0164] Interface control layer—not provided;

[0165] Lower gap layer—not provided;

[0166] Upper gap layer—not provided; and

[0167] Upper layer—not provided.

[0168] Each element was machined to form an integratedrecording/reproducing head such as that shown in FIG. 28 and a slidertherefor, with which data was recorded on and reproduced from a mediummade of a CoCrTa group material. For the recording/reproducing, thewidth of the track for writing data was set to 3 μm, the writing gap to0.2 μm and the width of the track for reading data to 2 μm. The curingprocess of the photoresist used for forming the coil portion of thewrite head portion was performed for two hours at 250° C. During thisprocess, the magnetization in the pinned and pinning layers which shouldessentially be oriented in the direction of the height of the elementrotated, as a result of which this element did not function correctly asa magnetoresistive element. Therefore, after forming the reproducinghead portion and the recording head portion, the element was subjectedto a magnetizing heat treatment in a magnetic field of 500 Oe for onehour at 200° C. The rotation of the easy magnetization axis of the freelayer towards the magnetization direction due to this magnetizing heattreatment was not observed in the substance from its magnetizationcurve.

[0169] Ten elements (or samples) were produced by the same productionsteps. The coercive force of the medium and MrT were selected to be 3.0k Oe and 0.35 memu/cm², respectively. Reproduction outputs were measuredwith these experimentally produced elements. The measurement results ofthe reproduction outputs of the ten elements are shown in Tables 1 and2. In the case where the plasma oxidization was not performed withrespect to the end faces of the MTJ film and the remaining pinned layer,none of the elements had a reproduction output equal to or greater than3 mV, and the reproduction outputs of the elements were not greater than1 mV for up to nine out of ten. When an element having an output equalto or greater than 3 mV is determined acceptable, the above yield iszero. The elements with substantially zero outputs have significantlysmall resistance, from which it is appreciated that bypass routes of thesense current are formed by the conductive area expanded by the burrand/or the milling residues of the pinned layer formed in the patterningprocess of the MTJ film. In contrast, in the case of the combination ofthe normal milling and the plasma oxidization, the elements hadreproduction outputs equal to or greater than 3 mV for up to eight outof ten, the yield thus being improved to 80%. It is appreciated thatbypass routes of the sense current have disappeared due to the plasmaoxidization of the end faces of the MTJ film and the milling residues ofthe pinned layer, resulting in an improved output. TABLE 1 (withoutplasma oxidization) Sample No. 1 2 3 4 5 6 7 8 9 10 Reproduction 1.1 0.40.9 0.3 0.7 0.9 0.7 0.5 0.1 0.9 output (mV)

[0170] TABLE 2 (with plasma oxidization) Sample No. 1 2 3 4 5 6 7 8 9 10Reproduction 3.2 3.2 3.1 2.4 3.0 3.1 3.3 3.3 3.0 1.9 output (mV)

EXAMPLE 2

[0171] Magnetoresistive effect elements corresponding to the thirdembodiment were produced.

[0172] For the MTJ film, a lamination of Ta (3 nm)/Pt₄₆Mn₅₄ (15nm)/Co₉₀Fe₁₀ (2 nm)/Ru (0.8 nm)/Co₉₀Fe₁₀ (2 nm)/Al oxide (1.5nm)/Co₉₀Fe₁₀ (0.5 nm)/Ni₈₂Fe₁₈ (5 nm)/Ta (3 nm) was used. After theformation of the film, a heat treatment was carried out for five hoursat 250° C. with a magnetic field of 500 Oe being applied in a directionperpendicular to that during the formation of the film. In thepatterning process of the MTJ film in the experimental production of theelement, all the layers of the MTJ film were patterned by means ofmilling down to and including the lowermost Ta layer. For the patterningof the MTJ film and the oxidization or nitridation of the end portionsof the patterned MTJ film, the following five methods were selectivelyused:

[0173] (1) Normal Milling Plus Plasma Oxidization

[0174] The MTJ film was milled by means of a normal milling apparatus ina pure Ar-gas atmosphere at 0.3 Pa, whereafter the film was moved into aplasma oxidization apparatus (ashing apparatus) in which the endportions of the MTJ film were oxidized. The conditions of the ashingprocess were such that the end portions of the MTJ film were contactedfor twenty minutes by a plasma generated in an atmosphere containing 0.3Pa of Ar and 0.1 Pa of O₂ by supplying RF power at 200 W thereto.

[0175] (2) Normal Milling Plus Spontaneous Oxidization

[0176] The MTJ film was milled by means of a normal milling apparatus ina pure Ar-gas atmosphere at 0.3 Pa, whereafter the end portions of theMTJ film was exposed to a dry oxygen atmosphere of 1 atmosphericpressure for one hour.

[0177] (3) Normal Milling Plus Nitridation

[0178] The MTJ film was milled with a normal milling apparatus in a pureAr-gas atmosphere at 0.3 Pa, whereafter the end portions of the MTJ filmwere contacted in a plasma oxidization apparatus (ashing apparatus) by aplasma generated in an atmosphere containing 0.5 Pa of Ar and 0.5 Pa ofN₂ for 120 minutes by supplying RF power of 200 W thereto.

[0179] (4) Milling in an Atmosphere of Oxygen Plus Ar

[0180] 0.3 Pa of Ar and 0.1 Pa of oxygen were simultaneously introducedin a milling apparatus, whereby the milling and the oxidization of theend portions of the MTJ film were carried out simultaneously.

[0181] (5) Milling in an Atmosphere of Nitrogen Plus Ar

[0182] 0.3 Pa of Ar and 0.1 Pa of nitrogen were simultaneouslyintroduced in a milling apparatus, whereby the milling and thenitridation of the end portions of the MTJ film were carried outsimultaneously.

[0183] For the comparison, further elements were produced on anexperimental basis without the plasma oxidization process. For theseelements, the following sub-elements were used:

[0184] Substrate—A 2 nm thick AlTiC layer on which alumina is depositedwith a thickness of 10 μm;

[0185] Lower shield layer—A layer of Co₆₅Ni₁₂Fe₂₃ (composition expressedin atomic percent; same applies in the following description) of 1 μm inthickness;

[0186] Lower electrode layer—Ta (1.5 nm)/Mo (80 nm)/Ta (3 nm);

[0187] Upper electrode layer—Ta (1.5 nm)/Au (40 nm)/Ta (3 nm);

[0188] Upper shield layer—A layer of Co₈₉Zr₄Ta₄Cr₃ of 1 μm thick;

[0189] Insulating layer—A 40 nm thick alumina layer;

[0190] Longitudinal biasing layer—Cr (10 nm)/Co_(74.5)Cr_(10.5)Pt₁₅ (36nm);

[0191] Interface control layer—not provided;

[0192] Lower gap layer—not provided;

[0193] Upper gap layer—not provided; and

[0194] Upper layer—not provided.

[0195] Each magnetoresistive effect element was machined to form anintegrated recording/reproducing head such as that shown in FIG. 28 anda slider therefor, with which data was recorded on and reproduced from amedium made of a CoCrTa group material. For the recording/reproducing,the width of the track for writing data was set to 3 μm, the writing gapto 0.2 μm and the width of the track for reading data to 2 μm. Thecuring process of the photoresist used for forming the coil portion ofthe write head portion was performed for two hours at 250° C. Duringthis process, the magnetization in the pinned and pinning layers whichshould essentially be oriented in the direction of the height of theelement rotated, as a result of which the element did not functioncorrectly as a magnetoresistive effect element. Therefore, after formingthe reproducing head portion and the recording head portion, the elementwas subjected to a magnetizing heat treatment in a magnetic field of 500Oe for one hour at 200° C. The rotation of the easy magnetization axisof the free layer towards the magnetization direction due to thismagnetizing heat treatment was not observed in the substance from itsmagnetization curve.

[0196] Ten elements (or samples) were produced by the same productionsteps. The coercive force of the medium and MrT were selected to be 3.0k Oe and 0.35 memu/cm², respectively. Reproduction outputs were measuredwith these experimentally produced elements. The measurement results ofthe reproduction outputs of the ten elements in each group are shown inTables 3 to 8. In the case where the plasma oxidization of the end facesof the MTJ film was omitted, two of the ten elements had reproductionoutputs equal to or greater than 3 mV, but the remaining eight had smallreproduction outputs wherein the outputs were substantially zero forfive of them. When an element having an output equal to or greater than3 mV is determined acceptable, the above yield is 20%, which is quitelow. The elements with substantially zero outputs had significantlysmall resistance, from which it is appreciated that the pinning layerand the free layer have been short-circuited by the burr formed in thepatterning process of the MTJ film. In contrast, in the case of thecombination of the normal milling and the plasma oxidization, theelements had reproduction outputs equal to or greater than 3 mV for upto eight out of ten, the yield thus being improved to 80%. The yield was70% in the case of the combination of the normal milling and thespontaneous oxidization, 60% in the case of the combination of thenormal milling and the nitridation, 50% in the case of the milling inthe atmosphere of oxygen plus Ar, and 40% in the case of the milling inthe atmosphere of nitrogen plus Ar. Thus, all the yield rates wereimproved as compared to the case where no such steps were taken. It isappreciated that, when the present invention is applied, the burr formedin the patterning process of the MTJ film is oxidized or nitrided intoan insulating material and thus does not cause the MR ratio to decrease.Although the combination of the normal milling with the plasmaoxidization exhibited the best characteristics in these examples, it maybe possible in the other cases to obtain characteristics comparable tothose in the case of the plasma oxidization by optimizing the conditionsfor the milling and the oxidization and nitridation of the end portionsof the MTJ film. TABLE 3 (without oxidization) Sample No. 1 2 3 4 5 6 78 9 10 Reproduction output 2.4 1.2 0 0.7 0 0 3.1 0 0 3.0 (mV)

[0197] TABLE 4 (with normal milling plus plasma oxidization) Sample No.1 2 3 4 5 6 7 8 9 10 Reproduction 3.1 3.2 3.0 0.8 3.1 3.2 3.0 3.0 0 3.0output (mV)

[0198] TABLE 5 +HC,1(with normal milling plus spontaneous oxidization)Sample No. 1 2 3 4 5 6 7 8 9 10 Reproduction output 3.2 3.0 0 0 3.0 3.03.1 3.0 3.1 0 (mV)

[0199] TABLE 6 (with normal milling plus nitridation) Sample No. 1 2 3 45 6 7 8 9 10 Reproduction 0 0.2 3.1 3.0 1.4 3.2 3.0 3.0 0 3.0 output(mV)

[0200] TABLE 7 (with milling in an atmosphere of oxygen plus Ar) SampleNo. 1 2 3 4 5 6 7 8 9 10 Reproduction 0.7 0.6 1.4 3.1 3.0 2.4 3.0 3.13.1 1.9 output (mV)

[0201] TABLE 8 (with milling in an atmosphere of nitrogen plus Ar)Sample No. 1 2 3 4 5 6 7 8 9 10 Reproduction 3.1 3.2 2.1 2.3 3.1 1.4 01.7 1.9 3.2 output (mV)

EXAMPLE 3

[0202] Magnetoresistive effect elements corresponding to the fourthembodiment were produced.

[0203] For the MTJ film, a lamination of Ta (3 nm)/Pt₄₆Mn₅₄ (15nm)/Co₉₀Fe₁₀ (2 nm)/Ru (0.8 nm)/Co₉₀Fe₁₀ (2 nm)/Al oxide (1.5nm)/Co₉₀Fe₁₀ (0.5 nm)/Ni₈₂Fe₁₈ (5 nm)/Ta (3 nm) was used. After theformation of the film, a heat treatment was carried out for five hoursat 250° C. with a magnetic field of 500 Oe being applied in a directionperpendicular to that during the formation of the film. In thepatterning process of the MTJ film in the experimental production ofeach element, all the layers of the MTJ film were patterned by means ofmilling up to and including the lower most Ta layer. The MTJ film wasmilled by means of a normal milling apparatus in a pure Ar-gasatmosphere at 0.3 Pa, whereafter the film was moved into a plasmaoxidization apparatus (ashing apparatus) in which the end faces of theMTJ film were oxidized. The conditions of the ashing process were suchthat the end portions of the MTJ film were contacted for twenty minuteswith a plasma generated in an atmosphere containing 0.3 Pa of Ar and 0.1Pa of O₂ by supplying RF power at 200 W thereto. For the comparison,further elements were manufactured on an experimental basis in which theplasma oxidization process was omitted. For these elements, thefollowing sub-elements were used:

[0204] Substrate—A 2 nm thick AlTiC layer on which alumina is depositedwith a thickness of 10 μm;

[0205] Lower shield layer—A layer of Co₆₅Ni₁₂Fe₂₃ (composition expressedin atomic percent; same applies in the following description) of 1 μmthick;

[0206] Lower electrode layer—Ta (1.5 nm)/Mo (80 nm)/Ta (3 nm);

[0207] Upper electrode layer—Ta (1.5 nm)/Au (40 nm)/Ta (3 nm);

[0208] Upper shield layer—A layer of Co₈₉Zr₄Ta₄Cr₃ of 1 μm thick;

[0209] Insulating layer—A 40 nm thick alumina layer;

[0210] Longitudinal biasing layer—Cr (10 nm)/Co_(74.5)Cr_(10.5)Pt₁₅ (36nm);

[0211] Interface control layer—not provided;

[0212] Lower gap layer—not provided;

[0213] Upper gap layer—not provided; and

[0214] Upper layer—not provided.

[0215] Each element was machined to form an integratedrecording/reproducing head such as that shown in FIG. 28 and a slidertherefor, with which data was recorded on and reproduced from a mediummade of a CoCrTa group material. For the recording/reproducing, thewidth of the track for writing data was set to 3 μm, the writing gap to0.2 μm and the width of the track for reading data to 2 μm. The curingprocess of the photoresist used for forming the coil portion of thewrite head portion was performed for two hours at 250° C. During thisprocess, the magnetization in the pinned and pinning layers which shouldessentially be oriented in the direction of the height of the elementrotated, as a result of which the element did not function correctly asa magnetoresistive effect element. Therefore, after forming thereproducing head portion and the recording head portion, the element wassubjected to a magnetizing heat treatment in a magnetic field of 500 Oefor one hour at 200° C. The rotation of the easy magnetization axis ofthe free layer towards the magnetization direction due to thismagnetizing heat treatment was not observed in the substance from itsmagnetization curve.

[0216] Ten elements (or samples) were produced by the same productionsteps. The coercive force of the medium and MrT were selected to be 3.0k Oe and 0.35 memu/cm², respectively. Reproduction outputs were measuredwith these experimentally produced elements. The measurement results ofthe reproduction outputs of the ten elements of each group are shown inTables 9 and 10. In the case where the plasma oxidization was notperformed with respect to the end faces of the MTJ film, there was oneelement whose reproduction output was equal to or greater than 3 mV, butthe reproduction outputs of the other nine elements were small. When anelement having an output equal to or greater than 3 mV is determinedacceptable, the yield is 10%, which is very low. The elements withsubstantially zero outputs had significantly small resistance, fromwhich it is appreciated that the pinning layer and the free layer areshort-circuited by the burr formed in the patterning process of the MTJfilm. In contrast, in the case of the combination of the normal millingand the plasma oxidization, the elements had outputs equal to or greaterthan 3 mV for up to nine out of ten, thus the yield being improved to90%. It is appreciated that, when the present invention is applied, theburr formed in the patterning process of the MTJ film is oxidized intoan insulating material and thus does not cause the MR ratio to decrease.TABLE 9 (without oxidization) Sample No. 1 2 3 4 5 6 7 8 9 10Reproduction output 0 1.3 0.9 0.4 0 1.6 0.3 3.1 0 2.4 (mV)

[0217] TABLE 10 (with normal milling plus plasma oxidization) Sample No.1 2 3 4 5 6 7 8 9 10 Reproduction 3.0 3.0 3.1 3.3 3.0 3.1 3.2 0 3.1 3.1output (mV)

EXAMPLE 4

[0218] Magnetoresistive effect elements corresponding to the fifthembodiment were produced.

[0219] For the MTJ film, a lamination of Ta (3 nm)/Pt₄₆Mn₅₄ (15nm)/Co₉₀Fe₁₀ (2 nm)/Ru (0.8 nm)/Co₉₀Fe₁₀ (2 nm)/Al oxide (1.5nm)/Co₉₀Fe₁₀ (0.5 nm)/Ni₈₂Fe₁₈ (5 nm)/Ta (3 nm) was used. After theformation of the film, a heat treatment was carried out for five hoursat 250° C. with a magnetic field of 500 Oe being applied in a directionperpendicular to that during the formation of the film. In thepatterning process of the MTJ film in the experimental production ofeach element, all the layers of the MTJ film were patterned by means ofmilling up to and including the lower most Ta layer. The MTJ film wasmilled by means of a normal milling apparatus in a pure Ar-gasatmosphere at 0.3 Pa, whereafter the film was moved into a plasmaoxidization apparatus (ashing apparatus) in which the end faces of theMTJ film were oxidized. The ashing conditions were such that the endportions of the MTJ film were contacted for twenty minutes with a plasmagenerated in an atmosphere containing 0.3 Pa of Ar and 0.1 Pa of O₂ bysupplying RF power at 200 W thereto. For the comparison, furtherelements were manufactured on an experimental basis in which the plasmaoxidization process was omitted. For the sub-elements constituting eachelement, the following were used:

[0220] Substrate—A 2 nm thick AlTiC layer on which alumina is depositedwith a thickness of 10 μm;

[0221] Lower shield layer—A layer of Co₆₅Ni₁₂Fe₂₃ (composition expressedin atomic percent; same applies in the following description) of 1 μmthick;

[0222] Lower electrode layer—Ta (1.5 nm)/Mo (80 nm)/Ta (3 nm);

[0223] Upper electrode layer—Ta (1.5 nm)/Au (40 nm)/Ta (3 nm);

[0224] Upper shield layer—A layer of Co₈₉Zr₄Ta₁₄Cr₃ of 1 μm thick;

[0225] Insulating layer—A 40 m thick alumina layer;

[0226] Longitudinal biasing layer—Cr (10 nm)/Co_(74.5)Cr_(10.5)Pt₁₅ (36nm);

[0227] Interface control layer—not provided;

[0228] Lower gap layer—not provided;

[0229] Upper gap layer—not provided; and

[0230] Upper layer—not provided.

[0231] Each element was machined to form an integratedrecording/reproducing head such as that shown in FIG. 28 and a slidertherefor, with which data was recorded on and reproduced from a mediummade of a CoCrTa group material. For the recording/reproducing, thewidth of the track for writing data was set to 3 μm, the writing gap to0.2 μm and the width of the track for reading data to 2 μm. The curingprocess of the photoresist used for forming the coil portion of thewrite head portion was performed for two hours at 250° C. During thisprocess, the magnetization in the pinned and pinning layers which shouldessentially be oriented in the direction of the height of the elementrotated, as a result of which the element did not function correctly asa magnetoresistive effect element. Therefore, after forming thereproducing head portion and the recording head portion, the element wassubjected to a magnetizing heat treatment for one hour in a magneticfield of 500 Oe at 200° C. The rotation of the easy magnetization axisof the free layer towards the magnetization direction due to thismagnetizing heat treatment was not observed in substance from itsmagnetization curve.

[0232] Ten elements (or samples) were produced by the same productionsteps. The coercive force of the medium and MrT were selected to be 3.0k Oe and 0.35 memu/cm², respectively. Reproduction outputs were measuredwith these experimentally produced elements. The measurement results ofthe reproduction outputs of the ten elements of each group are shown inTables 11 and 12. In the case where the plasma oxidization was notperformed with respect to the end faces of the MTJ film, there was oneelement whose reproduction output was equal to or greater than 3 mV, butthe reproduction outputs of the other nine elements were small. When anelement having an output equal to or greater than 3 mV is determinedacceptable, the yield is 10%, which is very low. The elements withsubstantially zero outputs had significantly small resistance, fromwhich it is appreciated that the pinning layer and the free layer areshort-circuited by the burr formed in the patterning process of the MTJfilm. In contrast, in the case of the combination of the normal millingand the plasma oxidization, the elements had outputs equal to or greaterthan 3 mV for up to eight out of ten, thus the yield rate being improvedto 80%. It is appreciated that, when the present invention is applied,the burr formed in the patterning process of the MTJ film is oxidizedinto an insulating material and thus does not cause the MR ratio todecrease. TABLE 11 (without oxidization) Sample No. 1 2 3 4 5 6 7 8 9 10Reproduction 2.2 0.7 0.1 0.2 0.8 0 1.6 1.7 3.1 0 output (mV)

[0233] TABLE 12 (with normal milling plus plasma oxidization) Sample No.1 2 3 4 5 6 7 8 9 10 Reproduction 3.0 3.1 3.1 3.1 0.9 3.1 3.1 0 3.2 3.0output (mV)

[0234] A magnetic recording apparatus manufactured in accordance withthe present invention on an experimental basis will now be described.This magnetic recording apparatus is provided with three magnetic discs(magnetic recording media) on a base and with a head drive circuit, asignal processing circuit and an input/output interface mounted on theback of the base. The apparatus is connectable to the exterior through a32-bit bus line. Six heads are disposed so as to face opposite surfacesof the three discs, respectively. A rotary actuator (actuator means) fordriving the heads, a drive and control circuit for the actuator and amotor directly connected to a spindle for the rotation of the discs aremounted in the apparatus. Each disc has a diameter of 46 mm and itssurfaces are used for data recording each in the range defined by aninner diameter of 10 mm and an outer diameter of 40 mm. An embeddedservo system is employed and the discs thus have no servo surfaces, sothat recording at a high density is possible. This apparatus is arrangedto be directly connectable to a small computer as its external storageunit. The input/output interface is mounted with a cache memory tocomply with a bus line whose transfer rate ranges from 5 to 20 megabytes per second. It is also possible to form a magnetic disc system ofa large capacity by providing an external controller and connecting aplurality of apparatuses of the above type to the controller.

What is claimed:
 1. A magnetoresistive effect element comprising: aferromagnetic tunnel junction film which comprises a free layer, abarrier layer immediately adjacent said free layer and a pinned layerimmediately adjacent said barrier layer; and an insulating layer,wherein said ferromagnetic tunnel junction film comprises a pattern of ametallic material sandwiched between one of an oxide and a nitride ofthe metallic material, and wherein said pattern of a metallic materialis sandwiched between said insulating material.
 2. A magnetoresistiveeffect element comprising: a ferromagnetic tunnel junction film whichcomprises a free layer, a barrier layer immediately adjacent said freelayer, a pinned layer immediately adjacent said barrier layer and apinning layer immediately adjacent said pinned layer, wherein saidferromagnetic tunnel junction film comprises a pattern of a metallicmaterial sandwiched between one of an oxide and a nitride of themetallic material.
 3. A magnetoresistive effect element comprising: aferromagnetic tunnel junction film which comprises an underlayer, a freelayer immediately adjacent said underlayer, a barrier layer immediatelyadjacent said free layer, a pinned layer immediately adjacent saidbarrier layer and a pinning layer immediately adjacent said pinnedlayer, wherein said ferromagnetic tunnel junction film comprises apattern of a metallic material sandwiched between one of an oxide and anitride of said metallic material.
 4. A magnetoresistive effect elementcomprising: a ferromagnetic tunnel junction film which comprises a freelayer, a barrier layer immediately adjacent said free layer, a pinnedlayer immediately adjacent said barrier layer, a pinning layerimmediately adjacent said pinned layer and a protective layerimmediately adjacent said pinning layer; and an insulating layer,wherein said ferromagnetic tunnel junction film comprises a pattern of ametallic material sandwiched between one of an oxide and a nitride ofsaid metallic material constituting said protective layer, and whereinsaid pattern of a metallic material is sandwiched between saidinsulating layer.
 5. A magnetoresistive effect element comprising: aferromagnetic tunnel junction film which comprises a free layer, abarrier layer immediately adjacent said free layer and a pinned layerimmediately adjacent said barrier layer, wherein said ferromagnetictunnel junction film comprises a pattern of a metallic materialconstituting said ferromagnetic tunnel junction film, wherein an oxideor a nitride of said metallic material constituting said ferromagnetictunnel junction film is present only at an end portion of said patternof said ferromagnetic tunnel junction film except for said barrierlayer.
 6. A magnetoresistive effect element according to claim 1,wherein said oxide or said nitride of said metallic materialconstituting said ferromagnetic tunnel junction film is present at anend portion of said pattern of said ferromagnetic tunnel junction filmand an upper portion of said barrier layer.
 7. A magnetoresistive effectelement according to claim 1, wherein said oxide or said nitride of saidmetallic material constituting said ferromagnetic tunnel junction filmis present at an end portion and in a peripheral portion of said patternof said ferromagnetic tunnel junction film.
 8. A magnetoresistive effectelement comprising: a lower electrode layer; a longitudinal biasinglayer formed on said lower electrode layer; a ferromagnetic tunneljunction film which comprises a free layer, a barrier layer immediatelyadjacent said free layer, a pinned layer immediately adjacent saidbarrier layer and a pinning layer immediately adjacent said pinnedlayer, at least a part of said free layer being disposed above saidlongitudinal biasing layer and adjoining said longitudinal biasing layerdirectly; an insulating layer formed at least on a part of said freelayer and said longitudinal biasing layer; and an upper electrode layerformed above said pinning layer and adjoining, at least at a partthereof, said pinning layer directly or with a protective layerinterposed therebetween; wherein one of an oxide and a nitride of ametallic material constituting said ferromagnetic tunnel junction filmis present only at an end portion of a pattern of said ferromagnetictunnel junction film.
 9. A magnetoresistive effect element comprising: alower electrode layer; a longitudinal biasing layer formed on said lowerelectrode layer; a ferromagnetic tunnel junction film which comprises afree layer, a barrier layer immediately adjacent said free layer, apinned layer immediately adjacent said barrier layer and a pinning layerimmediately adjacent said pinned layer, at least a part of said freelayer being disposed below said longitudinal biasing layer and adjoiningsaid longitudinal biasing layer with an underlayer interposedtherebetween; an insulating layer formed on at least a part of said freelayer and said longitudinal biasing layer; and an upper electrode layerformed on said pinning layer and adjoining, at least at a portionthereof, said pinning layer directly or with a protective layerinterposed therebetween; wherein one of an oxide and a nitride of ametallic material constituting said ferromagnetic tunnel junction filmis present only at an end portion of a pattern of said ferromagnetictunnel junction film.
 10. A magnetoresistive effect element comprising:a lower electrode layer; a ferromagnetic tunnel junction film whichcomprises a free layer, a barrier layer immediately adjacent said freelayer, a pinned layer immediately adjacent said barrier layer and apinning layer immediately adjacent said pinned layer, said film beingformed on said lower electrode layer, said free layer having a widthequal to or less than that of said lower electrode layer when viewedfrom an air-bearing surface of said element; a longitudinal biasing filmcomprising a film formed by laminating an insulating layer, at least aportion of which adjoins said free layer, and a longitudinal biasinglayer formed on said insulating layer, or an insulating material; and anupper electrode layer disposed above said free layer and adjoining, atleast at a portion thereof, said free layer directly or with aprotective layer interposed therebetween; wherein one of an oxide and anitride of a metallic material constituting said ferromagnetic tunneljunction film is present only at an end portion of a pattern of saidferromagnetic tunnel junction film.
 11. A magnetoresistive effectelement comprising: a lower electrode layer; a ferromagnetic tunneljunction film which comprises a free layer, a barrier layer immediatelyadjacent said free layer, a pinned layer immediately adjacent saidbarrier layer and a pinning layer immediately adjacent said pinnedlayer, said film being formed on said lower electrode layer, said freelayer having a width equal to or less than that of said lower electrodelayer when viewed from an air-bearing surface of said element; aninsulating layer adjoining at a part thereof said free layer; alongitudinal biasing layer disposed above said free layer and adjoining,at least at a part thereof, said free layer directly or with aninterface control layer interposed therebetween; and an upper electrodelayer disposed above said longitudinal biasing layer and adjoining, atleast at a portion thereof, said longitudinal biasing layer; wherein oneof an oxide and a nitride of a metallic material constituting saidferromagnetic tunnel junction film is present at only an end portion ofa pattern of said ferromagnetic tunnel junction film.
 12. A method formanufacturing a magnetoresistive effect element which utilizes as itsmagnetoresistive effect element a ferromagnetic tunnel junction filmcomprising the steps of: forming a basic structure of said ferromagnetictunnel junction film, an arrangement of a free layer, a barrier layerimmediately adjacent said free layer and a pinned layer immediatelyadjacent said barrier layer; and after patterning said ferromagnetictunnel junction film, doing one of oxidizing and nitriding an endportion only of the patterned ferromagnetic tunnel junction film.
 13. Amethod for manufacturing a magnetoresistive effect element whichutilizes as its magnetoresistive effect element a ferromagnetic tunneljunction film comprising the steps of: forming a basic structure of saidferromagnetic tunnel junction film, an arrangement of a free layer, abarrier layer immediately adjacent said free layer, a pinned layerimmediately adjacent said barrier layer and a pinning layer immediatelyadjacent said pinned layer; when said ferromagnetic tunnel junction filmis patterned, stopping patterning said film in the middle of the layersconstituting said ferromagnetic tunnel junction film; and oxidizing ornitriding at least a surface of that region of said ferromagnetic tunnelfunction film at which said patterning has been stopped in the middle ofthe layers.
 14. A method for manufacturing a magnetoresistive effectelement according to claim 12, wherein an end portion of said patternedferromagnetic tunnel junction film or at least a surface of that regionof said magnetoresistive element at which said patterning has beenstopped in the middle of the layers is oxidized by spontaneousoxidation.
 15. A method of manufacturing a magnetoresistive effectelement according to claim 12, wherein an end portion of said patternedferromagnetic tunnel junction film or at least a surface of that regionof said magnetoresistive element at which said patterning has beenstopped in the middle of the layers is plasma-oxidized orplasma-nitrided.
 16. A magnetoresistive conversion system comprising: amagnetoresistive sensor comprising a magnetoresistive effect elementaccording to claim 1; a current generating circuit for generating acurrent to be passed through said magnetoresistive sensor; and a datareading circuit for detecting a change in resistivity of saidmagnetoresistive sensor as a function of a detected magnetic field. 17.A magnetic storage system comprising: a magnetic recording medium havingplurality of tracks for data recording; a magnetoresistive conversionsystem according to claim 16; a first actuator for moving saidmagnetoresistive conversion system to a selected track on said magneticrecording medium; and a second actuator for driving said magneticrecording medium so as to rotate said magnetic recording medium.
 18. Amagnetoresistive effect element comprising: a ferromagnetic tunneljunction film which comprises a free layer, a barrier layer immediatelyadjacent said free layer and a pinned layer immediately adjacent saidbarrier layer, wherein said ferromagnetic tunnel junction film comprisesa pattern of a metallic material surrounded by one of an oxide and anitride of the metallic material, and said metallic material is saidfree layer.
 19. A magnetoresistive effect element comprising: aferromagnetic tunnel junction film which comprises a free layer, abarrier layer immediately adjacent said free layer and a pinned layerimmediately adjacent said barrier layer, wherein said ferromagnetictunnel junction film comprises a pattern of a metallic materialsurrounded by one of an oxide and a nitride of the metallic material,and said metallic material is said pinned layer.
 20. A magnetoresitiveeffect element comprising: a ferromagnetic tunnel junction film whichcomprises a free layer, a barrier layer immediately adjacent said freelayer, a pinned layer immediately adjacent said barrier layer and apinning layer immediately adjacent said pinned layer, wherein saidferromagnetic tunnel junction film comprises a pattern of a metallicmaterial surrounded by one of an oxide and a nitride of the metallicmaterial, and said metallic material is said pinning layer.
 21. Amagnetoresistive effect element according to claim 1, wherein said oxideor said nitride does not exist at the part of the air bearing surface ofthe magnetoresistive effect element.
 22. A magnoresistive effect elementaccording to claim 2, wherein said oxide or said nitride does not existat the part of the air bearing surface of the magnetoresistive effectelement.
 23. A magnoresistive effect element according to claim 3,wherein said oxide or said nitride does not exist at the part of the airbearing surface of the magnetoresistive effect element.